So, for me, the real tragedy of Dolores’s death on January 15 was that Dolores was Dolores’s psychiatrist in Ireland, Dr Seamus O’Ceallaigh, who had seen her on … and frighteningly delirious at a rented house on the estate at Adare Manor.

What are some amazing plot aspects/coincidences in the Harry Potter series?

Here is a neat little summary by Animesh Srivastava (अनिमेष श्रीवास्तव)

In 6th book, when Harry runs into Prof Trelawney, just before he and Dumbledore leave to get the Horcrux, she tells him about card reading for Dumbledore:
“ If Dumbledore chooses to ignore
the warnings the cards show —” Her bony hand closed suddenly
around Harry’s wrist. “Again and again, no matter how I lay them
out —” And she pulled a card dramatically from underneath her
shawls. “— the lightning-struck tower,” she whispered. “Calamity.
Disaster. Coming nearer all the time . . .”
Incidentally, Dumbledore dies in the chapter named “The Lightening Struck Tower”.

Earlier in the book:
“Two of spades: conflict,” she murmured, as she passed the place
where Harry crouched, hidden. “Seven of spades: an ill omen. Ten
of spades: violence. Knave of spades: a dark young man, possibly
troubled, one who dislikes the questioner —”

Conflict: Between Malfoy and Snape, Ron and Hermoine, arguements between Harry and Dumbledore, Harry and Malfoy, take your pick
Ill-Omen- Impending death of Dumbledore
Violence: Fight throughout the castle between the Order + DA and Death Eaters
Dark Young Man- Malfoy, Snape being the questioner
In a couple of lines, Trelawney summed up the whole book.

In PoA:
“The falcon . . . my dear, you have a deadly enemy.”
“But everyone knows that,” said Hermione in a loud whisper.
Professor Trelawney stared at her.
“Well, they do,” said Hermione. “Everybody knows about Harry
and You-Know-Who.”
Harry and Ron stared at her with a mixture of amazement and
admiration. They had never heard Hermione speak to a teacher
like that before. Professor Trelawney chose not to reply. She lowered
her huge eyes to Harry’s cup again and continued to turn it.
“The club . . . an attack. Dear, dear, this is not a happy cup. . . .”
“I thought that was a bowler hat,” said Ron sheepishly.
“The skull . . . danger in your path, my dear. . . .”
Everyone was staring, transfixed, at Professor Trelawney, who
gave the cup a final turn, gasped, and then screamed.
There was another tinkle of breaking china; Neville had
smashed his second cup. Professor Trelawney sank into a vacant
armchair, her glittering hand at her heart and her eyes closed.
“My dear boy . . . my poor, dear boy . . . no . . . it is kinder not
to say . . . no . . . don’t ask me. . . .”
“What is it, Professor?” said Dean Thomas at once. Everyone
had got to their feet, and slowly they crowded around Harry and
Ron’s table, pressing close to Professor Trelawney’s chair to get a
good look at Harry’s cup.
“My dear,” Professor Trelawney’s huge eyes opened dramatically,
“you have the Grim.”

Deadly Enemy:Of Course , Tom Riddle
Attack: Attack by Dementors in the Quidditch match
Danger: Well, again, dementors
Grim–>Death: Falling 50 feet is a sure way of dying. He was lucky Dumbledore was there.

A few minutes before this Ron predicted the following from Harry’s cup:
Work of Ministry: If he became Auror, its true
Unexpected gold: Harry did win 1000 galleons in Triwizard Tournament, even if about 2 years late.

In OOTP
“Professor Trelawney pointed a shaking finger at Professor Umbridge who continued to smile blandly at her, eyebrows raised.
ʹI am afraid… I am afraid that you are in grave danger!ʹ Professor Trelawney finished dramatically.”

She did get carried away into the Forbidden Forest by angry centaurs.

Adding to it, predictions about one person leaving around Easter(PoA), Harry’s prediction of Buckbeak escaping, 2 prophecies, no prediction in the series ever went unfulfilled.
Also, maybe Trelawney wasn’t a fraud after all. Whatever she said, did happen. Maybe she was predicting things sub-consciously all the time and didn’t realise it.

However, I think we need to take a step back and appreciate Jk’s genius here. Trelawney’s great-great-grandmother was Cassandra, who in Greek mythology was a Trojan seer who received the gift of prophecy from Apollo, but when she spurned his romantic advances, the god in his wrath cursed her that she would be ever correct but never believed. What a strange curse, one might think. One that would only ever work in an old story, where apparently everyone who hears her prophecies would be enchanted to disbelieve, even after several correct ones. One might even be tempted to think “Wouldn’t work on me, or anyone clever like me who can apply logic”. JK has managed to recreate this curse upon Cassandra’s imaginary great-great-granddaughter, for even though pretty much every singe prediction she ever made came true, who among us readers can honestly say they saw her for anything other than a fraud, who just so happened to have a gift she didn’t even know about? Because of her unfortunate personality hardly anyone could possibly take her seriously. Maybe the two prophecies she made while under the influence of the Second Sight, but all the rest was certainly scorned by myself, and (hopefully) almost every other reader, and the few times they did come true, surely they were lucky guesses? Brilliant! Absolutely brilliant! JK really fooled me on that one, only when I recently re-read the entire series (which I have done several times previously) did I realise how every single prediction made by herself (and even some of her students) came true. I’ll go so far as to say, the only one that hasn’t DEFINITELY come true is when she retracted her prediction regarding Harry Potter as a means of attempting to annoy Dolores Umbridge, stating that he would live to a ripe, old age, become Minister for Magic and have twelve children. We don’t know for sure that hasn’t happened, however.

Let me give another couple of examples: Her 13-people-at-a-table rule is known to have come true in regards to Sirius and Lupin, but who knew that she actually already predicted Dumbledore’s death in PoA? Including Scabbers (Peter) they were already 13 people seated before Dumbledore rose to greet Trelawney. He was indeed the first among them to die.
Also, she was ridiculed for believing Harry to be born in midwinter because of certain traits. Tom Riddle, whose soul was embedded in Harry was born midwinter, and shares the exact traits she used to describe Harry (“dark hair, mean stature, [and] tragic losses so young in life…”).

Please comment if you think I am missing something that definitely did not come true, I am prepared to discuss 🙂

Edit:

Steve Jones 1 vote by Akash Sarawgi commented:
“I’ll go so far as to say, the only one that hasn’t DEFINITELY come true …”

What about the one on 16th October – the one that Lavender takes to be the death of her rabbit but Hermione thoroughly deconstructs?

What about all of the prophecies foretelling Harry’s death?

And if you want to explain away those as her predicting the soul fragment’s demise, what about the one predicting a spate of colds with Trewlaney losing her voice? Didn’t definitely come true

Ps the “Dark young man” was Harry hiding behind a statue and overhearing her monologue”

Lasse Hyllested replied:

I realise using capitals may have seemed a bit aggressive, my apologies! But I do hold on to my claim. The instances you mention are very valid, and important, I think, because the key ingredient in JK’s masterpiece in the foretelling-genre (which incidentally derives from Tolkien, and in turn Icelandic sagas), seeing as they are what makes her unbelievable.

The point of foretellings and prophecies are, that they are ambiguous, as is so clearly explained by Dumbledore in regards to the one made about Harry and Voldemort. Their outcome depends on how they are interpreted, and CAN be dismissed as coincidence (although in JK’s world there are very few coincidences). That, I think explains the one about October the 16th, and perhaps the one about colds (I’m too lazy to pick up my copy to find the right part, but I think I remember something about flu breaking out), but I will give you that one, because I can’t remember for certain. You explain the one about Harry’s death yourself, but I might add, that her seeing a great dog in his future may very well have been a premonition about Sirius entering Harry’s life (her way of delivering her prophecies are a big part of the curse that has noone believing her). But there is also a very good case to be made about it being the Horcrux part of his soul dying. I mentioned her description of his likeness with young Tom Riddle, and on other occasions she does seem to have sensed the Voldemort part of him.

Yes, the Dark Young Man may very well have been Harry, with the questioner being Trelawney herself, like I said, it’s always ambiguous. But before I finish I will also mention the centaurs’ talk about what they could see in the stars – whatever it was that caused them to scorn Firenze when he saved Harry from his first encounter with Voldemort (in Quirrell’s body) and kept them from interfering with the Battle of Hogwarts, where Harry was in some way killed in the woods (a part of him, and had he chosen so himself, or had something gone wrong along the way, that might have been the prophecy fulfilled, only with the other dying. kinda like the “a great empire shall fall-prophecy).

Oh, and even most of the prophecies Harry and Ron made came true, as I’m sure can be validated in several other answers on this thread. There really are too many coincidences to ignore (although I do not claim that every single one is more than that) – this is not a conspiracy theory, this is beautiful authorship!

Martijn Coppoolse replied:
Making predictions that will come true some day isn’t all that difficult. Such predictions are also fairly useless.
It’s knowing when exactly they will come about that’s hard. And since that’s precisely where Trelawney fails consistently, I tend to see her as a fraud anyway.

Lasse Hyllested replied:
well, exactly like in the book, the way you interpret it, is what it becomes. You see a fraud, and that may very well be the case. I see a beautiful way of recreating and drawing inspiration from (as all great literature, and any kind of art, must) the sources. To stand on the shoulders of giants, as the philosopher said. Her way of recreating the Curse of Cassandra so convincingly, that almost a whole generation was fooled by one of the most analyzed book series in modern times. Based on my examples, compared with JK’s general style, it is to me crystal clear that this was her intention, and that she carried it out beautifully. But then again, I may be as woefully wrong as Humphrey Belcher, who believed the time was ripe for a cheese cauldron…