I hate it when YouTubers have intros that are like 30 seconds long. Just a little 5 to 10 second intro is fine, but they do not need to be like TV show intros.
They feel the need to make them as big and elaborate as they can, and they always have some crazy special effects - and the video itself hasn't even started yet!
And most of the time, they have to have obnoxious, blaring dubstep or trap music that melts your ears. Sometimes they do that in their outros, too, which scares the crap outta you when you have your headphones on and your volume turned up.
So yeah, they're basically the YouTube equivalent of those flashy opening/closing logos with the loud Moog fanfares from the 70's and 80's. I just wanna watch your dang video, not your stupid overdone intro.