Anti-nostalgia! What's something "everyone" in your generation loved that you never got into? Have you seen the light since, or do you still respond with apathy or even dislike?
The first thing that comes to mind is Pokemon. I remember during elementary school that kids would be showing off their cards or trading cards with others, and how it was considered "controversial" to the point where the cards would be taken away by teachers and they were banned from school property. So while I was aware of it, it wasn't something I got into. I never disliked it, I just didn't understand the hype because it wasn't really on my radar. It's one of those things you see in passing and know people are into but you're rather indifferent towards it. Now, of course, I know and understand more about it. I haven't really delved that deeply into it since there's so much out there, but I know more about the different kinds of Pokemon (beyond Pikachu, that is) and obviously from things like Pokemon GO and Detective Pikachu in recent years its popularity hasn't waned since it first entered the scene when I was a kid.
There are some other things, too, to a lesser extent like SpongeBob SquarePants. It was everywhere when I was in junior high/high school and I tried watching a few episodes here and there but I just didn't get it and never understood the appeal, and while it's become more an Internet meme nowadays I still have this indifference towards it. Sailor Moon is another one, where I wasn't even aware of it until I ended up watching the live-action Japanese show, Pretty Guardian Sailor Moon. With that, at least, I'm more aware of now and understand the appeal and the growth of the franchise as a whole.
I'm sure there are things I'm not remembering, but that really shows how indifferent I was towards things that many really enjoyed that I just either didn't care for or didn't pay attention to.