I don't usually wave first, but if I get waved at I retun the gesture. It's not really a big deal tho. The first human response to waves from an unknown person is usually, "do I know him?
", "is he/she waving at me?
", and that can be easily mis-interpreted as someone being a douche. I'd rather avoid that so I never wave first.
a smile on the other hand is different.
