I always think it’s funny when people I am acquainted with but do not really know me see me and can’t remember my name. Then they always say “Hey buddy” or “Hey man”. But my favorite is when they say “Hi guy”. I will then mention that Guy is my father’s name, just to see what they say. They usually will laugh or say “really?” and then excuse themselves awkwardly.
If I can’t remember someone’s name that I should know, I will just say “Hi” and leave it at that.