This one is more of a bike-handling gaffe- A buddy was riding next to me, and a yellowjacket wasp landed on his back. I said "hold still" and swiped the wasp off before it stung him. Every action has an equal and opposite reaction, and the ensuing wobble almost took me down at 20 MPH. Very scary. Next time he's getting stung. Don't try to throw anything from your bike, either- same problem- rock at dog.

Also- big horizontal frame, low clearance. Don't step off the curb while still straddling the bike. My voice was a register higher for about 20 minutes.