So i jst get this, im sitting by myself, i dont even think of anything funny, and i jst randomly start laughing for 5 seconds. then i stop and laugh again after 10 seconds. Also, when i hear a sad story of someone, or feel uncomfortable, when someone tells me bad news or something i start smiling - and i really dont want to. It's really odd, and people think im a total retard, they tell me sad stories, and i jst smile or even giggle a bit. And i dont want to, i feel sorry for the person but i still laugh. Why is this?