You're in the vegetation section of Tescbury's, because tomatoes are on your shopping list. Someone else has them on their list too, though, and is already picking some out of the crate. Do you:
A) wait?
B) say to them "excuse me", then without waiting for a reaction reach in and start picking some for yourself, then get huffy when they suggest that keeping your mitts out until they finish picking theirs is unlikely to ruin your day?
Asking for a friend.