Too much thinking actually ruins everything; the real test of intelligence is to figure out how to stop thinking once enough has been planned, too many "smart" people are so logical and rational that they end up too disconnected from their own emotions, their relationships suffer because they can't relate to others anymore (although they are somehow convinced they have human psychology figured out), they don't see the point of doing anything even slightly "foolish," they end up unhappy because they were too "smart" for their own good.