Feeling regret about having bought something is a very unpleasant sort of unhappiness. Here are some strategies to make sure you don't make purchases you regret: 1. Get in and get out. The more time you spend in a store, the more you're likely to buy. Even better: don't even go in the sotre. Then you definitely won't buy. 2. Beware of sale items. Beware of sale items, which make you feel like you can't afford not to buy, or limited-time offers, which make you feel like you have to take advantage of a special deal. If you don't need or want something, it's not a good deal, no matter how cheap it is. 3. Don't buy anything that you don't know you need--this is especially important with clothes. If you're not careful, you can buy a pair of pants marked down 75%, and then realize that you can't really wear them unless you buy the right shoes to go with them. 4. Be polite to salespeople, but don't feel like they're your new best friends. Don't buy something because you're worried about hurting their feelings or having made them do a lot of work helping you or explaining products to you. At the same time, be respectful of clerks' efforts.