Sometimes if I'm driving through the town I grew up in I think I'll spot a group of teenagers and I have a split second where I think it must be my childhood friends, before I remember that I'm a 40 year old woman and the friends have long since grown up too.
Same if I drive past my old schools, I expect to see one of my friends walk by on their way to school. Only for a moment.
Very occasionally I wake up and forget where I live and I think I'm in my childhood bedroom or in my old house then I realise.
It's like Deja vu but not the same.