Why do creationists have a problem with apes->humans?

To start, this isn't a "creationism is wrong, I'm so right" question. One thing creationists always seem to pick at it the idea of apes evolving into humans. Isn't unicellular to multicellular life more unbelievable? Or developing of lungs, or anything really? You can't deny microevolution, ie selective dog breeding and so on, and as apes are just really stupider, hairier humans, thats not that big a deal really?