Timing is perhaps the key to mom's hilarity. She will pick the worst time for you, to ask you for a favor. Whatever it is, she'll need it right this second, and she will not be happy if you say no. Could she have asked ahead of time? Probably.
Is she asking only when she knows you're busy? Absolutely.
Is it going to be worth being as angry as she will be? That's for you to decide.
So on a day when all of my cousins and I had decided to go to karaoke, she decides to stop one of my cousins as he is getting ready to leave. "Oh good, you're here. I need you to drive me to Redlands."
WTF? Redlands?!? She didn't even ask, but my cousin says no, and then she gets really scary. Like we just slapped her in the face and then knocked her to the ground.
I'm a "horrible" daughter and my influence has obviously permeated the rest of my generation. LOL