Let's say you see someone you know, say an acquaintance, at the office lobby. Maybe a colleague from another department, but not some close buddy. You are about 50m away from him, and assuming both of you have reasonably good eyesight, are able recognise each other at that distance. Do you :
a) Smile at him until he smiles back, then look elsewhere (like at your shoes or the cute guy walking behind your acquaintance) until you pass by each other?
b) Smile for awhile, then look somewhere else, then smile again until you are close enough for him to hear you say hello?
c) Look somewhere else until you are getting closer (say 10m away) and then smile and do some small talk?
d) Pretend you didn't see him in the first place, reach into your purse and fumble for some non-existent object, then suddenly look up until he's like right in front of you, then say "Oh hi, I didn't notice you just now"?
e) Pretend he wasn't even there, and get on with your life?