The Gemara Kesuvos already gave the answer to all such moral dilemmas:–
???? ??? ???? ??? ??? ?????? ??? ??? ??? ?? ????? ?????? ?????? ???? ??? ?? ??. V’dok. (??? ????? from R’ Shlomo Zalman zt”l before!)
Which means: The Gemara brings a story about R’ Acha who used to pick up Kallas and dance with her on his shoulders [which is obviously pritzus in our circles]. The Rabbanan asked him if they could do the same, to which he answered “If she is compared to you like a plank of wood , then go ahead. If not, then don’t!”
The same pretty much sums up all such dilemmas. If you feel, unlike most normal adolescent males, that your casual contact with women does not cause impure thoughts, then it is the most decent thing to do to greet (unless of course SHE will feel uncomfortable, which is sort of counterproductive). However, the rest of us humans should not.
(Dunno if I am generalizing too much or if its just me being honest!)