"Don't ride if you only have 1/2 a left leg!"
or
"hi, i am 12 and have never riden anything but a bicycle before, but my parents neglect me and bought me a new $15,000 bike. I am going to take it for a spin to learn how to ride. Surely it sin't much different from my old BMX"
Ooops. Mom and dad..can i have another one?