Keep things positive. You know who loves hanging out with people who complain too much or spend all of their time walking around with a sour look on their faces? No one. Even if you're in a terrible mood or think there's no justice in the world, try not to let it show when you're interacting with people. Start off by talking about light, positive topics, and you'll find yourself laughing in no time. People are much more likely to want to hang out with you again if they have a positive experience and feed off of your positive energy.