Just wondering if others have similar disconcerting/ confusing experiences...

Do you ever actuall physically recognise a person but they seem to know you far more than you know them? I don't think that makes sense so an example:

I'm working at a supermarket for the summer and while I come acrosss various annoying/ horrible people, occasionally I get a few I recognise. One such person knows I've got into university, and treats me very friendily asking me how things are going there. On one meeting he told me a long list of names, saying they were of teachers who had retired, and did I remember them? I had no idea what he was talking about but I guessed he was once a teacher at one of my schools perhaps, or at another school and had confused me with another pupil. But then yesterday he was with his wife (familiar again, no idea who she is though) and something he said then revealed for certain he knows who I am... I just don't know who he is or how he knows me.

Another example: there is a really weird man I know. He's odd because I think he is old but his face is almost line-less so I can't decide his age but he must be at least 30 but probably older I think, maybe 40+. I'm 21 and I don't know wherever I met him but I remember I've been saying 'hi' to him when I've been seeing him around (again no idea where I met him). My dad said,' Did you meet him in the hospital?' but I'm pretty certain I didn't because I've met others who were in hospital at the same time as me and I know who they are. Anyway, a few weeks ago this man came up to me in the supermarket and said,'So, have you been going out recently then?' or a similar phrasing to that. I had no idea why he asked that! I'm pretty certain I'd never ever have been out anywhere with him - all I can think of is that I've met him through my friend but since he's way old er tha me I don't know. It's really weird. I must know him from somewhere because he is familiar to me yet a total stranger?

Anybody else get similar situations?