We all know people—likely professional colleagues, as they rarely last as friends—who view a person's worth solely in terms of what the person can do for them. “Hi, it’s nice to meet you. Can you drive me to the car repair shop over lunch?” “Oh, you finally have a weekend free to yourself after eight weeks of work and house guests? Great! Can you help me move into my new apartment?”

Of course, true friends are glad to help one another out, and over time it’s a mutually beneficial relationship. You want to help your friend, because you genuinely want to make their life easier and better. Too many people, however, don’t wait for that goodwill to develop before presuming they’re entitled to impose upon your life.