Bishop's big ol' thighs.
How Storm couldn't use her powers without explaining what she was going to do.
Gambit in general.
Every time Beast quoted the classics.
The fact that Jean Grey was basically naked and no one seemed to care.
Professor X's hovering wheelchair.
That thing where Storm transformed her clothes with lightning.
And also that one time Nightcrawler showed up.
How Wolverine was always going on vacations to see old girlfriends in Japan or fight Sabertooth or something.
The Days of Future Past storyline.
That one time Wolverine read the Bible in a church.
That one time Rogue had to give Cyclops CPR and absorbed his powers.
The Danger Room.
Everything about Magneto.
How Wolverine could only use his claws to slice robots because it was a kid's show and humans aren't allowed to get sliced.