Most days I let it go.
Every once in a while I slip. My most recent inappropriate reaction happened about three months ago. A kid in a car buzzed me very close while leaning on his horn. About 100 yards ahead I saw him pull into the left turn lane and stop to wait for his arrow. The passenger side window was down so I pulled up, pointed my Airzound directly into his car and let 'er rip. Then I simply pedaled away.
I really didn't feel good about losing my cool like that at the time. Now as I remember it it's kind of funny.