Hahaha... I'll say ones that actually I have done...
You might be obsessed with Psychonauts if...
...the highlight of your year is getting to visit Double Fine, even more than getting to go to Japan.
...You take your copy of Psychonauts to Japan with you, even though you don't have a Playstation there, just so you can look at it every night.
...The only way your friends can convince you to go on roller coasters is by giving you Psychonauts style merit badges after each one, and letting you jump on nearby benches afterwards singing the little merit badge song and doing the pose.
...Whenever someone mentions an insane asylum, you brighten up and ask "Thorney Towers!?!?"
...Whenever something gets knocked over you mention TK
...You give a speech about Psychonauts and Double Fine to a class of Japanese girls, and have them all think you're crazy because they have no idea what you're talking about. And then wonder if maybe they'll send you to Thorney Towers if you're crazy enough... >.>
...You get special card protectors for your Psychonauts playing cards.
There's more, I'll add them later when I think of them.
It fortunately is have such friends person's. I hat you.