Oh, here's another note: I work in a pet store. I pride myself on working in one of the finest pet stores, where the animals are all well cared for and there is no hesitation to rush any sick/injured animal across the street to the excellent vet.

We specialize in reptiles and fish, but we have other critters as well. Of these, my least favorite by far are hamsters. I have been bitten by hamsters for no apparent reason dozens of times. I understand that if your hand goes over them they will associate it with a big predator, that's fine. However, when the animal is already out and sitting in my hands, not being restrained in any fashion (me sitting on the floor so that if they jump they don't get hurt) and BITES me anyways, this is silly. Russian dwarves in particular.

Hamsters in my experience are another generally nasty animal. We do occasionally get friendly ones in, but on the whole they are bitey and unpredictable.