As I discussed a while back, I don't really eat lunch in the field. I'm fine with other people eating lunch, but I tend to work right through the work day.
With that said, I may still get irrationally annoyed if someone:
1. Orders a pizza without telling anyone or asking if anybody else wants to order
2. For pickup right before we head out on a four-hour drive
3. Eats the large, greasy pizza with lip-smacking gusto
4. Does not offer to share, and
4. Leaves the remaining half of the pizza in the cab of the truck for the rest of the drive
Seriously, if you're going to order something big and aromatic and then trap me in the truck with it, the least you can do is an offer to share a slice.