To grab food from your plate at the last review, in collaboration with others, without offering to others before it is considered rude. As the show was not greedy.
The final piece of the plate to eat food produced jointly with others without first offering them to others is considered impolite. It represents the excesses or no kindness.
To pick up the last piece of food dish to eat together with others without offering to others before it is considered impolite. That represents gluttony or uncooperative.