My T knows absolutely everything about me for a couple reasons -

a) I've known him for 16 years as a friend, prof, priest, and T
b) I tell him absolutely everything in therapy and through email and text...there's nothing we don't talk about, and I always text him jokes and memes and stuff. We both have a really good sense of humour, and we share that.
c) He gets to see "student" me at school. He jokes that the last $5 of my session fee goes towards observation fees in class. I told him to stop watching me and I'll just pay him $5 less lol.