Everyone fails sometimes. Indeed, it is doubtful that we could ever learn if we never failed at anything. The sign of intelligence is not the absence of mistakes, but, instead, learning from those mistakes so that they are not made again and again (Dweck, 1999; Sternberg, 2000; Sternberg, 2002). An intelligent person can be forgiven for making mistakes, but perhaps not for making the same ones over and over again.

Almost all of us know supposedly intelligent people who make mistakes too often and who fail at what they do too often. It is as though their intelligence doesn't mean anything when they have to actually live in the real world. Clearly, intelligence is not enough for successful performance in the everyday world, no matter how broadly intelligence is defined. People can come into the world with the best brains in the world, grow up with every intellectual advantage, read all kinds of books (like this one) about how to become smarter – and still make a mess of their lives. Unless they can overcome the stumbling blocks that can get in the way of ideal intellectual performance, they may find that their intelligence is of little value.

This chapter discusses twenty stumbling blocks that can get in the way of even the smartest individuals. For the most part, these stumbling blocks are not strictly intellectual ones.