So long and Thanks for all the fish

Have you ever bump into a long lost friend, have a quick chat with them and then, there was a moment of silence where both of you can't decide what to do next?
We haven't seen each other for over 5 years, we were semi-closed once (eg we had hours long chats on the phone about life and such)
So what do we do;
Do we hug, exhange contact details and promise to meet up again?
Do we hug, exhange contact details and promise to meet up again, but never do?
Do we just smile and say well it was nice to see you again and walk away?

Well we smile and walk away in the opposite direction.... what would you have done?