What's a good way to deal with a workplace bully? I think so far I've done a poor job in handling them..?

I've left a few jobs (more than one were full-time positions, too) when I worked alongside a bully. I recently bailed a temp gig due to daily facing a condescending, nasty supervisor, whose own boss was quite a quiet, leave me alone, type. I keep on running into these jerks at various jobs. I consulted with some people regarding this; I heard that some workplace bullies are really miserable creatures (unhappy with their lives, etc..) while others see their 'targets' as employees who appear threatening. I recall more than once when a bully, before his/her (yes some of the bullies I faced were women) confrontational insulting side was revealed, would, in an almost crestfallen manner, remark to me how quickly I was learning stuff on the job (industry software, etc..). Then, the following day, the hell would begin. Two stinging comments I heard recently from one were "are you sure you worked in an office before?" and "can you speed it up - when performing clerical duties", with real anger in their voices. I know I'll face these jerk types in the future; how can I handle them better? One reason I would leave jobs with bullies, is that I feared I would snap if I stayed longer, and really curse them out. That would be pretty bad, and leave an ugly mark, and I could forget about getting any references either).