These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
YMMV: House of M
Bizarro Episode: The nature of the crossover caused a few for some titles that tied in to it. Many Marvel comics did an issue set in the House of M reality that had little or nothing to do with those books' ongoing storylines.
Crowning Moment of Funny: Hulk's line "Hulk hates stupid giant cyborg things. Hulk hates Australia. And most of all Hulk hates personal pronouns."
Crowning Moment of Heartwarming: Captain America's reaction to seeing Hawkeye's uniform hung up on the wall of the derelict Avengers Mansion, next to a newspaper clipping reporting on Clint's death. He immediately realizes what it means, and smiles.
Strawman Has a Point: Nobody actually answered Spider-Woman's Skrull doppelganger why it was necessary to set the world back, although the whole "humans are a persecuted minority" thing would presumably be enough to convince the heroes to change it back.
Wanda was still a serious danger and the fact that she was so powerful she could change the history of the planet only made it clear she was even more dangerous than they imagined, since she was still mentally unstable. It's hinted that she is driving them to overthrow her after all, if subconsciously, so the fact that she's working to destroy her own world probably isn't a very good omen. Once the house of cards crashes down it's also clear she didn't even like the new world, so it's not hard to imagine she might have rewritten reality all over again, and again and again, until the universe was in serious peril. Granted, though, someone really should have pointed that out in-story.
When Spider-Man learns that setting the universe right would mean losing both the resurrected Gwen Stacy and the young son they had together forever. And don't get started on Uncle Ben.
Before that, the two page spread of the notable events of Peter's life coming back to him, including the deaths of Uncle Ben & Gwen Stacy. Going through all that again, in mere seconds, and with Uncle Ben & Gwen asking if he's alright as he regains his composure? Peter immediately takes off. The other heroes all have looks on their faces that suggests that they're thinking that restoring Peter's memories wasn't the best decision, but Luke Cage sums it up perfectly.
"That was damn awful."
Hawkeye. He's alive in this world, he's dating Mockingbird... But then he loses her when she goes to Wakanda, gets his memories back and knows that, not only has she left in House of M, she's believed to be dead at that point. Him demanding to know why Wanda killed him is heart-breaking.
Luke Cage trying to call Jessica Jones, his fiancée in the real world, only to get through to an answering machine message of her & Scott Lang. Cage then asks if Spider-Man tried to contact Mary Jane, but Spidey admits he didn't because she's better off without him, pointing to her flourishing career. When Cage tries to reason that it's not true, Peter simply states "But we're not, and she is."
Spider-Man, after his memories are restored and he realises that Uncle Ben and Gwen Stacy should be dead. It's even noted with Shadowcat noticing that Spidey's not making his usual sarcastic remarks, and is just silently hunched over in the corner. And then in the epilogue, he desperately pleads with Doctor Strange to erase his memories of the resurrected Uncle Ben & Gwen Stacy, and his young son Richard. By the end of it, you just want someone to give the poor guy a hug.
For that matter, Doctor Strange emerges from the event looking and sounding somewhat shattered and saying his failure as Sorcerer Supreme is to blame for it all.
Hawkeye. He finds out that he was killed by a friend and can't handle it, then he's killed again, and then he's brought back at the end. The worst part is that he takes off alone again when he's brought back at the end. He's with Mockingbird in House of M — who chooses to leave for Wakanda. When he gets his memories back, he discovers that she's dead in the real world.