Soft spots in your thinking
Being human, we are prone to make certain errors in our thinking. Quite a bit of recent research has gone into discovering these standard errors, which particularly afflict the self-taught (who lack the benefit of an instructor who points out the common errors). This post talks about just some of the common errors, and it’s worth reading.
Also, I recommend Russo and Schoemaker’s book Decisions Traps, which was revised as Winning Decisions. Either is excellent. If you read both, the second provides a review and reminder of the points in the first, plus takes you a little further. The books are particularly useful if you ever make decisions.