People Who Expect Others To Do Their Work For Free

My sister agreed to babysit this summer. That was okay with me, but when I went to ask my mom if I could go to my best friend’s house, she butted in with, “no, because you have to babysit for me all this week while I’m at volleyball.” I wouldn’t have minded this if I had already agreed to do it, but she just assumed I would do it. Now I can’t see my best friend for a really long time. And my mom can’t do math right—I said that I watched them for ⅓ of the day, so I get ⅓ of the money, but that wasn’t good enough for her. So I calculated it and it turned out to be a little more than ⅓, and now all she does is complain about how much money she’s losing. And she thinks she’s going to pay me way less. Again, I would not mind doing this if she had discussed it—and pay rates—over with me first.