Social Dilemma-Is It Rude to Eat The Last Piece of Shared Food?

Today's social dilemma came about after a conversation we had at dinner last night.  Went out with some friends and coworkers and we went to a place where the food is served family style.  It was Italian so there was a little bit of everything, pizza, stuffed shells, pasta, etc.   Anyway, the last piece of pizza was on the plate and I wanted it so badly, but I didn't take it.  I always feel like I should never take the last piece just in case someone else wants to eat it.  Just as I was thinking that, a very close friend of mine took the last piece.  And I started laughing and told him what I was thinking.   He laughed and said I always think the opposite.  If there's only one piece left of something, you better grab it quickly before someone else does.  Ultimately we ended up splitting the piece of pizza, but it made me think.  He and I have completely different ways of eating at a group dinner.   I guess it goes back to being in a big family and always wanting to make sure that everyone had enough so I would wait to make sure they did.  Again, he said he grew up in a big family and he knew he had to quickly get whatever he wanted or it would be gone.  So simple question today, is it rude to take the last piece of food when you're out with a group of friends or family, or is it perfectly fine to do that?  Let me know what you think on the 98-3 TRY Facebook page.