Credit goes to my wife for this, for summing up an idea that I'd always thought of as incredibly important to play having teeth in four small words: IC Punishment, OOC Reward.
(For those unfamiliar with the terms, IC means In Character and OOC mean Out of Character, a distinction that comes up enough online that it's useful to have a shortcut for referencing them.)
The idea is a pretty simple one. When you need to make bad things happen to another character - either as a GM or as another player in a large game like a LARp or MUSH - the responsible thing is to find a way for the thing which is bad for the character to be fun for the player. This comes up most commonly when the issue is punishment. One character has committed some sort of offense, and the decision regarding how to deal with it is in the hands of another player.
In this situation, the common response tends to be a "What would this character do?" sort of approach, and that usually means something like tossing someone in prison, killing or maiming them or otherwise putting them in a position where they won't be able to play.
Now, in contrast, consider stories that begin with punishments. There have been plenty of them, and they follow a certain formula. Either the prison is someplace dramatic (and of course inescapable) or the punishment is a task which is impossible, and what follows is the adventure of overcoming these things.
I like to call these "briar patches", after the famed story, and they're what to look for in these situations. Something undesirable to the character that will be lot of fun for the player. Characters are brought before the king for stealing, and they're punished by being sent to rescue the king's daughter. Sure, it's dangerous, and IC, the characters are in a terrible, undesirable situation - get killed by this king or get killed on this fool mission. That just sucks for them. But for the players? That's adventure right there. If that's not what they're looking for, then something else is wrong.
They're easy to spot because they have a clear course of action. If a prison's story is that it's inescapable, then obviously it's there for the players to escape. If a task is impossible, then it's clear it must be done - isn't that rather the point? In contrast, tossing someone in a cell and walking away to play somewhere else means they go nowhere.
The alternative, which is frankly more work, demands that the imprisoned character receive more attention. They're being a good sport to play something that is not fun, so you need to step up an make it more fun. It works, sure, but isn't it easier just to make the situation fun in the first place?
This idea applies to more than just punishment. Really, it's a backdrop for any game where you're going to do things the players love but the which the characters would hate. And it's not universal - some players will not enjoy any kind of bad thing happening to their characters, but I think those are few and far between. More often, you will have players whose experience suggests that bad things happening to the character means that they won't have any fun. If you can demonstrate otherwise, you may be surprised how willing they are to engage.
Give it some thought. Just keep an eye out for briar patches, and see how well they work for your game.
I'm off at Origins this week, so I'm posting som old articles. This one's from 2007, and the original and some discussion can be found here.