Mall Meetings

I was in a shopping mall the other day with a frnd and I happened to twice bump into ppl I knew. On the 1st occasion it was just casual hi wi while on the 2nd I was trying to avoid the person! 2 different responses to very similar situations! Now being a tester and what not, I got thinking - what are the differnt possible ways a chance meeting like this could take (actually I guess the "thinking" part had more to do with my being bored in that place, having just accompanied a frnd who was actually shopping, than being a tester ;) ).
Anyway, here is my take on the case -

Scenario1: I meet a good frnd.
Response: I say hi hello and exchange greetings and go our way.

Scenario2: I meet a person who is office acquaintance - with whom I havent exchanged any dialogues at work itself. But I know he exists and he knows I exists as well!
Response: Well...maybe I will smile and nod in acknowledgement (ie if the other smiles back :-) ).

Scenario3: I meet a person from work, with whom I may have talked a few times - but in meetings only, in group - not one on one.
Response: Umm...maybe a courteous hi, how are you etc. If nothing else comes to mind, then maybe ask question to which I already know the answer...like 'So you shopping here?' types :).

Scenario4: I meet a person I knew long long back - so long back that I know the face, but cant put a name to it!
Response: I would try to avoid the person - afraid if the 1st question that guy pops is - 'Do u remember me, my name'?. What would be more embarrasing is if that person does remember my name. lol !

Scenario5 (worst scenario): I meet a person who I knew long back and I never liked him/her when I knew them.
Response: Hmmm. I would try to avoid the alley that that person takes, for the most part. But I know what would eventually happen, given my luck with such things - I would take a turn and BAMMM come eye to eye with that sameeeeeeee person!!! In the back of my head I would be like - Shitttt, look the other way, look the other way! Get past him as fast and still as normallyyy as possible! :)))

There are various other scenarios possible, I am sure; but like its said of testing - a product can never be 100-percent-tested - I cant prepare myself in advance of all the possible scenarios. Besides, whats the fun in stage-prepraing a meeting, more impormptu it is, the more pleasant it is.