I really like YouTube and there are a lot more things I like about it than I don't. I do have some peculiar annoyances, though. Of course I don't like the clickbait and exaggerated claims to get you to the video watch page, but that's all over the internet and media. Same with stuff like Smosh. It's just not my kind of humor. But I don't like reality shows or sitcoms, either. That kind of stuff is everywhere, not just YouTube.
These are the things that bug me the most: I don't like that you can't use the minus/dash to search for results that specifically don't contain the following word. I don't like how some comments give you email notifications, others give you "bell" notifications, and still others show up on the lock screen of your phone, and while there is a good amount of overlap between them, some of them only show up in one of those places. The comments page on the full site on a computer shows all of them, but a lot of them are replies to other comments and those are listed farther down where the original comment is. You can sort them by date, but it doesn't take into account date and time of the replies. Related to comments, I don't like that I can't turn off the spam filter if I want to. To a lesser extent, sometimes it is annoying that there are so many channels on YouTube with such a redundancy of content that it makes it hard to find what I'm looking for a lot of times.
I don't personally mind the sub4sub requests very much. I hardly ever get any of them, though. I also don't really mind people commenting just to get people to view their channel. I'm just neutral to it. It's the same as someone commenting and then deleting it. I thought I had a new comment and then found out I didn't. No biggie.