Well yes, it really depends on what you mean by having a “poor attitude”.
But extremes aside, if someone’s attitude is just “off” or “a bit grumpy” about being part of a ministry… what should you do? Tell them to stop serving until their attitude is right? Or, tell them to just righten-up their attitude?
I think there’s two lenses to consider this question… is there a human aspect? Is there a gospel aspect?
It could just be that life is all too much at the moment, and they’re stuffed. They might just be tired. That is, they might have a good gospel attitude (if you asked them) but they’re just not aware of how they are responding or how they’re appearing and speaking to other people. That means you’re in a position to offer wise counsel about how to plan to serve (avoid late night tv the night before, etc.) and how to smile and talk to people while they’re serving. You’re helping them do what they already think is a good thing to do… just better… without the apparent chip on their shoulder.
But, it could be that they don’t want to serve Jesus and his people, or they feel like that role is beneath them. They might think they shouldn’t really have to serve and that Christian service should be like the self-serve check-outs at the shops… sure you have to try a bit hard, but there’s certain perks to it?!? They might not think their life is Jesus’ possession.
Even in many of these circumstances, I’d want to suggest they keep serving while you work through it with them.
Because serving isn’t something Christians choose to do… it’s part of our DNA… we follow a servant king. Telling someone to stop serving is like telling a fish to stop swimming because they find the water too warm.
If possible have them keep on swimming, keep on serving and all the while, keep helping them feel the privilege of serving their saviour.