feeling listless

Philosophy Gala puts into words one of my life rules:

"I think a good guiding principle, though, is the No Assholes Rule. Crude, I know, but bear with me. What this means is that you make a decision — now — never to deal with or get involved with anyone who is an asshole. (I’m using the term “asshole” as a blanket term to mean anyone who is rude, callous, unprofessional, unethical, vile, disrespectful, etc. You can mix & match terms as you like!) Basically, the less assholes you deal with, the less chance there is that you’ll be tempted to compromise your ethics. Sometimes it can be hard to tell whether someone is cool or not, but trust me when I say that the more you listen to your intuition (your “gut”), the better your asshole radar will become. If your intuition is singing out “No, no, no!”, listen! & then act! A lot of mistakes & potential ugliness can be avoided by engaging this principle."

But how do I know if I'm not the asshole?