I'm thinking of telling my date after we have sex that I have an STD.
If you have an STD you should tell her before you two do anything.
I don't, I just want to piss her off.
You shouldn't lie about having an STD. You could cause your partner a lot of worry.
I think I will. I hate her because she's cute.
I don't understand how you can hate someone that you are planning on sleeping with. Do you not want to have a relationship with her? Even if that is the case, you should not lie about potentially contagious diseases because it will just cause undue worry, and won't accomplish anything worthwhile.