If it is safe to do so, I stop pedaling, turn a bit sideways on my saddle and look back to make direct eye contact with the driver. This I believe adds a human element to me the cyclist, and lets the driver know I can ID him in a lineup.

Conversely, when I am cycling in heavy traffic, I probably act like your SUV friend. I shoot every gap made available to my by hesitant motorists. The difference is: I won't kill them if something goes wrong. A bit of scratched paint is at stake.

When driving a motor vehicle I leave early, take my time, and become very courteous. I am fully aware of the amount of damage I could do by driving like an @$$