Garrett nailed it when he wrote: "When you find yourself finally at the point where you really are frustrated to see the price of your company go up, you know you're now maturing into ... a Rule #1 Investor!"
Like Davey Crockett said (according to Walt Disney), "First be sure you're right. Then go ahead." I loved that line from the TV show. When I was 9 it made so much sense. Life is easy. Just be sure you're right, then go ahead. Then I grew up and volunteered for the Army during Vietnam, married and divorced twice, got all into a guru in India and thought a million dollars was a fortune. I've been wrong so many times down started to look like up to me. And all the while, I was seriously trying to follow Crockett's advice. My conclusion is that in life's decisions, only God knows for sure and the best you can do is follow a good set of rules about what's right and wrong. With investing, on the other hand, things are simpler. It is possible to "know you're right".