I use my signal first as a request, second as an announcement. If there is a move that makes it clear that the other person is just being a dick, I get forceful. That's just me. I'm young. I'll live forever. Right?
Second, don't be so quick to judge Southern California drivers. Sure, they may be a little heavy on the pedal and freak out over a drop of rain - but at least they're not afraid to merge on the freeways, an all too frequent situation I've witnessed in Utah. I think the best drivers have spent some time driving in MI.
Or I might be biased.