I volunteered to help out another team about 2 months ago because they were struggling. So I helped them and ended up saving the day for them. But now that I've helped, no one is taking any responsibility from that team to take over the work I started, so now it's become mine for the life of it, even though I don't work on that team. So what that means is that I have to work over Christmas, along with members of that team, to take care of this part of my new responsibility. I was glad to help them, but I am resentful that I now have to work when normally I wouldn't over the holiday. There's many unfair things that go on at my workplace, and this is just one of them. I should have just trained someone on their team to do it, so I don't have to.