From my experience I learned one thing.

AVOID DUMB PEOPLE.

Never work for dumb people. Never work with dumb people. No matter how beneficial for you the deal is (or seems to be) so far, if you notice that people you rely on are dumb, just quit as soon as you can.

Dealing with dumb people almost always backfires hurting you financially and psychologically.

I don't say that you have to quit as soon as somebody around you does something dumb, but you definitely should quit as soon as you learn that someone you rely on is dumb, even if he hasn't been dangerous for you so far.