Fall back dude!!!!!! who are you?

The funniest thing happened to me 2day that I'm sure happened to every1 at some point in time. I'm getting of the train after work & homie walks over to me "like you Webb what's good." So me being the nice guy I am 0:-) instead of embarrassing him and saying sorry who the F are you, I respond "whats good my dude I haven't seen you in a minute how you. " I try to keep on walking in stride and say stay up and go on but my merry lil way. For some reason dude walks the same way I got to walk and carries on a conversation with me like we were best homies, the sad thing is I don't know this dudes face from anywhere. Should I have hit him with the awkward words like excuse me who are you or did I do the right thing lol? I know I'm not the only person that this has happened to. What do you do when someone is excited to see you and u can't even remember them?