Without a doubt, metalcore. So much of it is literally one note breakdowns, and they're typically very boring. The vocals also sound stupid normally.
Behind I would say nu-metal and glam/hair. There are some good nuggets in both genres (for example, the s/t slipknot album is mostly very good and interesting), but I find I have to dig through a lot of shit in order to find something that captivates me.
Edit: I'm just so curious as to why nu-metal seems to have disappeared as a genre in a fairly short period of time within the metal community. Metalheads used to talk so much trash about nu metal so much and the people who listen to it.