As I see it, there's a time to be assertive and a time to not create ill will. And personally, if I'm not going to give a tip for picking up my pizza, I'm not going to be so obvious about it, especially at a place that I go to often.Yikes, what a socially awkward penguin you are. I have no problem writing in a 0.I always tip 20% or round up. The only time tipping annoyed me was when I ordered pizza, went to pick it up, put my bank card in the machine and it had an option for tipping on the display. I didn't want to look bad, so I punched in a tip. I'm used to tipping at restaurants, but I wasn't used to this. Whenever I went back, I made sure to bring cash.