So, I had a thought and wanted to see what other DMs think. 

An NPC curses a player character with a curse that means any time they are asked politely to do something by anyone they must do that thing. I might link it to the request requiring the word please to be activated or such. I would only let the player in question know, but would try as best I can to hide it from the remainder of the party as the party don't always agree and can be a little rowdy.

To my mind it doesn't seem too mean because the player character has the option to carry the task out in their own way. So, for example you are asked to give someone their weapon. If the person requesting it fails to specify the weapon they're asking for the player could hand over their basic dagger rather than the magic sword the requester really wanted. So, unless the person asking is both polite and specific there would be loopholes for the player to minimise the effect on their character.

You're basically using your DM power to remove free will. There can be specific moments where such things like a Geas spell can be used but you're taking it a step further. Player agency is important and while there can be things here or there to impede it where reasonable, your curse is not reasonable and could remove it entirely. It's basically a "as DM I will control your character whenever I want" thing. 

Absolute NOPE. Avoid at all cost. 

Yeah, this sounds a bit like a code activated Geas where the code is so common it might as well not be there (using “Password” as your Password).

I mean, it might not come to a ton if most people don't *know* about the curse, so it might only come in clutch at dramatic story moments. AND you could always rule in favor of creative interpretations of what "helping" might be and how self aware the character can be while under the effects of the curse.

I for sure though, would pitch this idea (vaguely if you don't wanna give away all the deets) to the player and see if they're OK with a consequence like that happening to their character. 

I'll play Asmodeus' Advocate and offer a potential way of doing it, you'll just need to target the right player and have some trust in them. You'll need them to make a saving throw but this should be easy enough to sneak in during play, if/when they fail this, deploy your curse as follows:

Hand the chosen player a note or send them a message/DM/email depending on how you are playing. The note says the following:

"You have been cursed! The curse is a Curse of Agreement. You are free to interpret this and roleplay it as you see fit but keep the following guidelines in mind: 1) This Curse cannot compel you to hurt yourself or do something that would obviously end your characters life. 2) Should anyone view your character with any magic detecting effects or abilities you have an Aura of Enchantment and Necromantic Energy surrounding you. 3) The Curse can only be lifted with a Remove Curse spell, 4) This effect is permament until removed. These guidelines are not known to your character, these are for your out of character reference."

Then leave it to the player to decide how this curse manifests in game, is it one where they feel compelled to agree with everyone or every course of action that is suggested? Do they instead decide that everything needs a written contract before proceeding? etc. The right player should be able to use that for some interesting roleplaying without derailing things too much.

Would you kindly choose a different approach to your curses?

Quote from Rob76 >>

I'll play Asmodeus' Advocate and offer a potential way of doing it, you'll just need to target the right player and have some trust in them. You'll need them to make a saving throw but this should be easy enough to sneak in during play, if/when they fail this, deploy your curse as follows:

Hand the chosen player a note or send them a message/DM/email depending on how you are playing. The note says the following:

"You have been cursed! The curse is a Curse of Agreement. You are free to interpret this and roleplay it as you see fit but keep the following guidelines in mind: 1) This Curse cannot compel you to hurt yourself or do something that would obviously end your characters life. 2) Should anyone view your character with any magic detecting effects or abilities you have an Aura of Enchantment and Necromantic Energy surrounding you. 3) The Curse can only be lifted with a Remove Curse spell, 4) This effect is permament until removed. These guidelines are not known to your character, these are for your out of character reference."

Then leave it to the player to decide how this curse manifests in game, is it one where they feel compelled to agree with everyone or every course of action that is suggested? Do they instead decide that everything needs a written contract before proceeding? etc. The right player should be able to use that for some interesting roleplaying without derailing things too much.

 I mean this is a great point and as Level 10+ characters I've set the saving throw to just WIS 15. It's not difficult to achieve for many of them, and they do have two clerics in the party both of whom have access to remove curse. Basically, I was imagining that this is probably only going to linger round for a session maybe two for the players to have a laugh and then be done with. 

I was already planning that the details would be in a note handed privately to the player, and already planning to let them interpret how they had to carry out the curse.

As to those moaning about it removing player agency, it really doesn't. If one NPC is asking the party to complete a quest the players are a helpful bunch it won't make much of a difference if the NPC has been sneaky and done something to ensure that the quest is completed...at least not until they find out and head back to the NPC. I was actually thinking more of what happens when player characters find out a fellow character has this curse. I can see them deciding to tease the cursed comrade for a little while. Mainly minor annoyances, things like getting cursed player to open doors, carry stuff etc. 

Such a curse doesn't eliminate player agency as much as you'd think. Consider Bender in Bender's Big Score. Just because he had to return an item to the scammers who installed a computer virus on his brain, doesn't mean he couldn't utilise that 'trust' in him on the part of the scammers to later steal the item from the scammers.

For example. NPC asks player character politely to steal an item and place it into the safe when retrieved. 

There is nothing in that instruction that prohibits the player from then failing to close the safe, or even taking the item out of the safe once placed inside. Heck said player character could even break back into where they stole it from originally and return the item if they wanted.

It's this kind of loophole that my players are usually great at highlighting and exploiting. It plays into their wheelhouse. They're the type of party that goes to the Dwarven Excavation in Dragon of Icespire Peak tells the dwarves that a dragon is about and then heads off because 'they've followed the quest instructions to the letter.

It really all depends on the player whose character is the one being cursed. Some players will think it’s great fun, others would be deeply upset by it. Get the player’s consent first is all I’ma say on the subject.