2. Vision and Wanda Maximoff (Scarlet Witch)
I will say this right off the bat - I do not agree with this couple being disliked, but that's also because I'm incredibly biased since I adore Wanda/Scarlet Witch. Alas... Some people do not share my sentiment.
Fans felt that Vision and Wanda being a thing was just slipped into the movie while we watched the Avengers assemble. They say if you blinked, you might've missed the memo that these two went from "Hey, we're kinda on the same superhero team" to "Let's share our digital and magical life essences." The leap from colleagues throwing magical punches together to exchanging gooey looks over a paprikash recipe left said fans scratching their heads. Some have argued it was like skipping the first half of a movie and trying to piece together the plot from the middle - confusing and a bit unsatisfying. I say nay, but that's just my little opinion.
Now, no matter how you initially felt about them as a couple, it is undeniable that WandaVision later turned their love story into a fascinating, heart-wrenching saga that had us all rooting for them (and maybe shedding a tear or two). But before that, in the movies, sure - their romance felt like it was on fast-forward. One minute, Wanda would be manipulating minds and Vision would be phasing through walls, and the next, they'd be playing house in domestic bliss. It came across a bit like the MCU decided to throw a surprise party nobody was prepared for, and some fans were left wondering, "When did they even start liking each other?"
TL;DR - It's not that some fans are against love blooming amidst chaos; it's just that they wished they'd been given a bit more time to RSVP to the relationship party. But they're wrong, so there's that.