8. Half Of Marvel's Superheroes - Civil War
When it comes to superheroes becoming public enemy number one, it'd be insane to not mention Civil War, wherein every hero who doesn't agree to the Superhuman Registration Act becomes a criminal in the eyes of the law - and an enemy to everyone who complied.
This naturally led to a very uncomfortable scenario wherein these renegade heroes were hunted down like dogs by their former friends, which gets actively painful at parts where you see good friends forced to turn on one another, due to being on different sides of the law. The ending is similarly painful, as it sees Captain America be arrested for leading the faction against the Registration Act - and while this is nowhere near the first or last time Steve Rogers has been arrested, there's something about seeing Cap in handcuffs that stings every time.
Hilariously, all this suffering would be made totally pointless mere years later, when Iron Man would be forced to destroy all registration records in order to prevent Norman Osborn accessing them for his own means.