The title of this post comes from one of the best moments in The Gamers  (which is laugh-out-loud brilliant all the way through — a must-see, if you’ve never heard of it), in which the party’s thief tries to steal someone’s pants in a bar. Why? Because he can, of course!
It’s hilarious in the movie, but in actual games actions like this can be a sign of player boredom or frustration.
Stealing his pants, in general terms, describes any PC action that is random, unrelated to the game at hand, funny and at least mildly disruptive. (Unless you’re playing a humorous RPG, like Paranoia or Toon, in which case none of this applies — it’s just par for course!)
There are two red flags in that list: disruptiveness and being unrelated to the game at hand. In my experience, PCs do some pretty random things, and there’s nothing at all wrong with being funny (every game can use a little humor ), so those don’t count as red flags.
Doing something totally unrelated to the adventure at hand can be a sign that the player is lost. Perhaps there are too many loose ends, and they can’t see anything important in their flashlight beam . With no clear course, why not do something totally off the wall?
It can also be a signal of boredom. If nothing exciting is happening, it can be pretty tempting to do something peculiar just to liven things up. As a player, this one fits me perfectly — if I’m bored or frustrated, I steal someone’s pants. There’s are time when that’s excusable, and times when it’s not — but as a GM, it can be a useful signal to watch for.
The other element — being disruptive — can be a bit sneaky. Often, stealing someone’s pants won’t be wildly disruptive, just mildly so. It’s not the same thing as, say, randomly killing a major, friendly NPC. It might not even seem disruptive right off the bat.
But any disruptive behavior (on either side of the screen) signals a problem of some sort. Exactly what the problem is can run the gamut, from boredom/frustration (as above) to personal issues with another player, or (at the far end of the spectrum) passive-agressive dissatisfaction with the game.
Lastly, stealing someone’s pants can also just mean that it’s time for a break. If you’ve been gaming for hours non-stop, maybe the pants-stealing player just needs ten minutes, a cup of coffee and time to decompress.
Next time a PC tries to steal someone’s pants in one of your games, pause for a moment and look at the situation. It might not mean anything (sometimes a cigar is just a cigar) — but it could be a sign of frustration, boredom or the need for a break.