At the beginning of a class/course/seminar, show a glass 1/2 full of water. Ask, now is this glass 1/2 empty or 1/2 full? Shows tendency towards pessimism or optimism. Do you tend to concentrate on what’s there or what’s missing? As far as class is concerned, want to encourage students not to look for what is missing during the course but how what is being presented can be used and what needs it can fill.