Pizza parties for me have either been where

1. I work in service industry and am allowed to grab a slice but I must eat it at my desk and keep working

2. I work in technology industry and my boss is well aware we're going to have to work through lunch for the 3rd day in a row because of massive outages and orders pizza

3. Sales is coming into the building and they're celebrating with catered lunch but we get pizza as a consolation