I'm going to get into an argument with my gf and not pick her up
Why would you not pick up your girlfriend?
I'm busy and I don't feel like it.
You solution seems very immature. It's wrong to leave your girlfriend stranded. She may break up with you.
She is not my responsibility and I'm always right about these things.
You agreed to pick up your girlfriend and refusing to do so is now an abdication of your responsibilities. Leaving your gf stranded is not correct. Imagine if she did the same to you.