Here's the thing...

I am not paid to watch the kids my mom is paid to watch. Not only am I not paid to do it, when I have to do it all day for several days in a row when she goes out of town the only reason I do get paid is because my step-dad tells her to pay me. I love her, and I know she loves me, but she makes me so mad with the babysitting. If I tell her no, I can't watch them she generally ends up guilting me into doing it anyway. She uses keeping the boys as her reasoning why I should help her, but you know what, I paid her for when she watched the boys while I was in school. I even paid her when she wasn't watching them! Yet she throws that in my face constantly.
Today she calls and asks if I'll come over and watch the kids she babysits during naptime so she can go to the store and get groceries before my step-dad and siblings get back from their youth trip. I told her I would but John is getting off work early today and him and I have a lot of running around to do. I don't know what time he'll be getting home and neither does he so I can't give her a timeframe or anything. She acts all angry and like I should cancel all of my plans because she comitted herself to babysitting today but has decided she'd rather do something else. If she knew she would want to get things ready and done before they get home tonight (which knowing my mom she planned this all along) she should have told them she just couldn't babysit today. But she called me a few hours ago and told me well fine she's bringing Zach home and maybe she'll get him in a few hours, she's not sure, but obviously she'll be too busy for him to be with her. WTH?! Okay since I won't do her job she's going to punish him? Yeah, real freaking mature.