I'm not going to get my mother a mother's day card
Why would you avoid doing that?
Why should I care, I'm just the son of that stupid bitch.
Be careful not to upset your mother. This could come across in a pretty mean way, and your mom has done a lot to raise you.
I'm a kid trying to make a point. The rest of the day is ruined if I have to go get a card.
Getting a card won't take long so your day won't be ruined. Try to show your mom some love on this day and respect her so she is happy. You have the chance to really make your mother's day special here.