You know who you are.
You can't pass up a good book cover when you see it.
You quite possibly cannot forgive a bad book cover, either. You know the kind I mean. The ones that have an image on them that has NOTHING TO DO WITH THE CONTENTS OF THE BOOK! (I yelled this in print because it's the sort of thing that M and I yell in person when we find books like this). Maybe there's a girl on the cover of a book with a male main character (this didn't bother me in the case of John Green's Paper Towns, but holey moley, have I heard other people rant about that, both online and in person). Or there's a white girl or guy on the cover of a book with a minority main character.
Or the ones that simply don't convey the era/setting/content/tone of the book adequately - a cutesy cover on a serious book, say, or a Very Serious cover on something that isn't a very serious book, or a cover that skews too old or too young for what's in between the covers or, in some cases, a MISSED OPPORTUNITY (same disclaimer for the yelling). I mean hey - if you've got an awesome steampunk story in between the covers, wouldn't you want to see an image that says "steampunk" on the cover? Scott Westerfeld's Leviathan and Behemoth sure do. So do Gail Carriger's books for the adult market, Soulless, Changeless and Blameless. Not so the books by D.M. Cornish (at least the original coves), Ysabeau Wilce and Jenny Davidson.
So Leila over at Bookshelves of Doom is doing something about it, to whit: A MAKE YOUR OWN COVER CONTEST! Details can be found there, but the deadline is December 15th.
I, for one, cannot wait to see what you all come up with.