Whether he’s alone, with friends, or with his new girlfriend, greet him with KISS (Keep It Sweet and Simple). Resist the urge to run away shrieking, hide behind the nearest lamp post, roll your eyes or pass a sarcastic remark. If there’s an awkward silence, you can defuse it by asking how he’s been, if he’s still working / schooling at the same place, etc.

Don’t get into deep topics If you’re not in the mood to make small talk, then just smile, say it’s been nice bumping into him, but you’ve got to run for an appointment which you’re already late for. Smile or wave graciously (not vigourously or stiffly) as you leave, and keep your head up high as you walk off.