Motorists Are Dumb

I was riding back to the house today on Randall when a little car sped up to get ahead of me as I crossed the turn lane to University.  The motorist instead of slowing down to pass behind me sped up to pass in front of me. He nearly ran out of room to make the turn before the island and then had to cut hard right only to stop behind three cars at a red light. What is it about cars that turns people into idiots? In this case no one was hurt but he saved zero time, as he had to wait for the cars already stopped at the light to go. Why is it that driving a car seems to make motorists incapable of slowing down even when speeding up brings about no discernible benefit?