Don't say "The last one there is a rotten egg": unless you're absolutely sure there's a slow kid behind you.
You can teach an old dog new tricks with the right kind of doggie treats.
One thing you can't pretend to be is funny.
Nobody can pedal the bike for you.
If you want to see a shooting star, you might have to spend a lot of nights looking up.
It's easier to see the mistake on someone else's paper.