Seriously!! If someone says they don't want pizza, then fuck off. I never understood that 'well, just one bite...It won't kill you.' mentality. What if OP was vegan too? What if he was allergic to cheese or tomato sauce? Either way, that's harassment in my book. Pizza has nothing to do with work, so it has nothing to do with refusal on the job. I had that issue with fantasy football gambling pool at my old job. I'm not a sports fan and I was the only woman who worked in a hardware shop where everyone gambled during that time period. I refused to since A) I don't want to gamble my money and B) I don't enjoy American Football.  I got the whole silent treatment thing whenever I walked into the backroom to put away my coat and bag every morning. Whatever.