"Pretty Good." I say that almost every time someone asks me that. It's such a boring question. Small talk is boring. I hate asking it and answering it. It's a filler for conversation 'pretty good' prevents people from asking any further. "Hey man how are you" "Good" 'you' 'yea I'm alright' END. Done. I guess its like a chore, people etiquette. But then again I guess you need time to break that first barrier, like when you see a person you haven't seen for a long time. A apart of you wants to talk, another parts want to avoid cause you know its probably just small talk. Then you put a smiley face on engage in small talk, disengage after a while. Smile also goes.
Or maybe a talk would of been nice, since you did have a pretty boring day. But the other person thinks your busy heading off to someone, and you probably think the same think. Especially if they are with their friends. Maybe its the fact that we think the other person is always busy, maybe thats the reason why we don't indulge in more deeper conversations in these spontaneous moments.