I’m probably more empathetic than average, but when I’m driving a car bicyclists give me acute anxiety of the “You or I make one wrong move and you’re dead”-sort, as well as the “am I doing this right?”-social anxiety (since driving near bikes doesn’t have strictly-taught rules like other aspects of road safety) and I know many people manifest their anxiety (especially social anxiety, which is rampant in driving: just watch for the “green light but nobody is going”-glance) as anger/aggression.