My favorite is "so you should let me take you out." "No." "Come on it will be fun. Just give me a chance." "No." "Why not? I'll show you a good time. Maybe you can show me a good time later." "Because no." "Do you have a boyfriend or something?"  What the fuck does that have to do with anything? I'm not going to save your fat ego with that excuse. I don't want to go out with you.  That's it.