You know what they are. Even if you're a totally regular person otherwise, they're the weird little quirk that's unique to you. The sort of thing so trivial it never gets brought up, but seems odd when it does. The thing only your closest friends know — or maybe not even them. Or perhaps something silly that you avoid mentioning, so you don't get made fun of.
Me?
I absolutely adore Clippy, that little animated paperclip that floats around in Microsoft Word. If he's not out when I start Word on someone else's computer, the first thing I do is get him. I think he's cute. In fact, I think he's awesome. His little animations make me giggle. I apologize to him when I stare at the screen too long and he falls asleep. When I'm pushing hard at 2 AM to get a report out at the last minute, I have conversations with him. I've delayed upgrading Office for 3 years because they removed him in version 2007. Clippy, I <3 you!!