I started a new campaign with a brand-new set of players. After the first evening, one of the PCs reacted poorly to a decision made by another PC and 'went home'. This reaction was totally in character and was not meant by the player to be antagonistic. But, now the party has a problem: it needs to regroup.
It hit me that this would be a perfect roleplay Skill Challenge opportunity, except with a PC instead of an NPC as the target (convince the PC instead of "convincing the Duke"). The players agreed to try it.
There are a few problems with this idea:
- I need to figure out a scenario if the PCs fail without it seeming like a 'railroad'
- The target PC needs to constrain their responses to the roll of the other PCs, thereby limiting their personal roleplaying style or desires (if the other PC rolls successfully, the target PC needs to agree, even if the details aren't 'perfect'). GMs can adapt NPCs on the fly without issues. A player won't want to alter their character as a result of another's actions (or a dice roll).
Is there another approach that I should take? Are there solutions to the problems I describe above?
The player did not over-react, nor did she do anything that I think is wrong. The situation occurred after the evening's adventure, so nothing was ruined by the action. What happened was that the decision was made and executed without thinking about how it would affect the next day. The only problem is that it created an issue for the next game day: How would the PC rejoin the group for the next adventure? I wanted a chance to introduce Skill Challenges to the players and thought that this would be a way to allow the players actions as well ("always saying 'yes'"). Only afterwards did I realize the potential pitfalls to my own decision…
"My character would do that" should never be used as a "justification" (more likely excuse) for game-wrecking behaviour. It's not a simulation, it's a game. Everybody wants to have fun.
One thing is doing something that will make the in-game situation difficult while still providing a positive gaming experience. But good role-playing should never lead to a bad time playing the game.
I don't know the details of what happened in-game, but since you said the player did not want to damage the game, you could work out something like this. The offended character comes back the next day with a speech like: "I couldn't sleep over what you did to me and what you'll keep doing if nobody puts you in line. I'll keep an eye on you from now on, and make sure you never do that again." And/or come back just to show the other character they behaved wrong and how they should do it better next time.
Rich Burlew also touches on this topic in his article Making the Tough Decisions (particularly in the section after "Decide to React Differently")
And to directly address your question itself: I strongly believe you should work this out through freeform role-playing alone. Letting a PC coerce another PC into doing something using a game mechanic is asking for trouble, it would eventually backfire. Players are supposed to control their characters' actions as long as they maintain free will. Charm-type spells and physical effects (such as pushing or chaining someone) is a different story, but "soft" effects like diplomacy or intimidate shouldn't be usable by one PC on another.