8. If you think, "I really shouldn't do this, but...," stop immediately at "but."
Everything I have done after "but" has been a huge glaring mistake. Shooting off an angry response to a friend after she sent me a thoughtless email. Jumping off a stool while pregnant. Eating the whole weird shriveled-up black pepper in the take-out Chinese Magic 7 Vegetables dish. Pouring water on my husband's head even after knowing better (as articulated in rule 1). "But..." is the car alarm designed by the human mind to stop you at the point of stupidity. Ignore it at your peril.