I'm going to ditch a project partner and do the whole thing individually
Why do you want to ditch a project partner?
They aren't a very good student and they might bring my grade down.
I understand you're upset, but you shouldn't ditch people. It's not the right thing to do. I think there are better solutions to this problem.
I'm going to do this and I don't give a shit if you have a problem with it.
If you ditch your project partner they might tell their teacher you were uncooperative. Instead of being worried about them letting you down, try helping your partner and getting them on the same page you are. That way they'll be appreciative and may be willing to return the favor in the future.