Then I would have to say the "Oh this is so nice! I love it! Check out my gallery " is the worst. Because it's pretty selfish and really defeats the purpose of commenting at all if you ask me. It's an empty compliment! They don't really care about your art one way or the other. They just want you to see what they have and they're barging into your profile/artwork/journal pages to do it.
If that's how we're gonna do things, then McDonald's might as well walk straight into Burger King and start putting Big Mac flyers up in all their stores.
I love your art work!! And this is kind of annoying I know but PLEASE check out my gallery, give me badges, and like all my photos!!!
These are generally the most annoying. Or the random role-play I'm just like, "Huh"? I don't mind if people say stuff kind of off topic though. Not that big of a deal. And the "I will never be as good as you!" I have never gotten that comment myself I would see it more of a compliment.
The order of votes it's in right now is the order I hate from worst to tolerable. I hate self-advertising, or spam. I hate those people that hops from profile to profile posting the EXACT SAME comment.