I'm going to ignore my girlfriend for a day
Why would you choose to ignore your girlfriend?
I don't want to hang out with her anymore today
I understand needing some alone time; everyone does. But it's probably best to discuss it with her and ask for it, since ignoring your partner can be hurtful to them.
No I don't want to hang with her because she burned my dinner and tried to feed it to me.
Well, I'm sure she didn't mean to do it. Look, people make mistakes all the time. That's not a good reason to ignore them.