The document lists 13 habits that can contribute to unhappiness, such as measuring one's success by others, dwelling on failures, hanging around negative people, setting unrealistic goals, having a pessimistic outlook, undermining others' happiness, holding grudges, worrying excessively, being angry, frowning, ignoring those in need, feeling entitled, and yelling when not getting one's way. The author aims to point out patterns that may be causing readers' unhappiness so they can work on removing these stumbling blocks from their lives.