One of the big ones is vegetarianism. We're not all vegetarians. The Dalai Lama himself for the longest time wasn't a vegetarian. Oddly enough, in my experience, there's two sets of people for whom this seems somewhat prevalent. The first group comprises American convert Buddhists who often expect that other Buddhists should be vegetarians or that they themselves should be a vegetarian as part of being Buddhist or that they feel bad because they're not vegetarian and they're Buddhist. The second group I have found comprises non-religious Chinese people whose experience with Buddhism seems to be encounters with Chinese vegetarian Buddhist monks, and therefore expect all "good" Buddhists to be vegetarian.
So next time I encounter a representative from the latter group, I'll ask them to explain what I observed in my local Chinese live seafood market yesterday (click image for detailed view):
It's the closest thing to a real Dharma Burger I've ever seen - it's KFC Dharma!