Here goes another one of my theories!!! And explination behind the picture.
You may be an aquaintance to Jeff, but that doesn't mean you're exempt from the Murder List and/or games. One for example is the "I'm going to find a way to really piss you off"
Game, and "Hide and Seek, but don't let me catch/find you"
game. Niether of those are fun for the Human side of this relationship. They usually end up with him killing you or you're in a really bad mood for the rest of the day.
That means if Jeff wanted to play the least harmful of the two, he'd watch your actions and behaviors around other people. For example, I really REALLY hate it when people jump out of fucking no where at me. People trying to take my hat off, or people trying to put a hat on me. I hate it when I get surprised hugged(I really don't like hugs in general unless I give you the okay to hug me, in Jeff's case, its never okay for him to hug me, you never know if he'll pull a knife out and stab you). Jeff being the sneaky bastard he is will take his new found information and put it to work. And there you have it.
Jeff's such a troll, but I guess thats just how he rolls sometimes.*EDIT*
I'll have to remember to add in a few other things to this drawing when ever I have time to. *END EDIT*
Jeff belongs to whom ever created him
Art by ~Axilla-15