Must be a contradictory thing to discuss. Yeah, we love bands, we trip on them and some of us end up being fanboys. But isn't there something about your fav band that irritates you or something you would like to see the band stop doing over and over again? Lemme start with God Dethroned. I love that band. But there is just one thing I hate. They most always seem to have some stupid part where the vocalist screams yah yah yah yah......... oooooooooooooooooooooooooooooooooooooooooooooooh. Either both or one of those things and it sounds terrible when they are both done one after the other. There was a time(especially during the Blaze era) where the moment you hear the intro/lead of a Maiden song, you know what the tune of the song is going to be like, or there will be a lead tune followed by a similar vocal one immediately after that. Also felt this thing about a soft intro bursting into something heavy gets too repetitive with Maiden. They are not a major irritant though, it's pretty tolerable. But guess I tend to overlook those cos I'm a Maiden fanboy.
Apart from that, I really don't find anything that I hate about my other fav bands. Wat about the other folks?