I wouldn’t dare defile Douglas Adam’s memory by not mentioning that you should keep a towel with you at all times, but my second contender is a surprisingly short three-parter:
- never lie.
- never tell the whole truth.
- never pass up a chance to use a real bathroom.
Ride smooth not fast has won me some mountain bike races.
I first heard it in the context of carpentry, but I’ve since heard it in kitchens as well.