This is a gender-neutral example, but one of the best ways to forestall stress/creepiness when meeting new people was pretty well summed up by a PUA. He suggested setting up a time by which your conversation has to end when you start it. ("Oh, I want to make the next bus, but I've got five min"). One thing that is stressful about being approached by someone you don't know, especially if they seem a little off is having to simultaneously carry on a conversation and try to plan an exit. If you set up an exit when you approach and precommit ending the conversation then (unless you both are in the middle of something quite interesting) it's easier to just be present for the conversation.