Continuation of the story

Okay, so how does this development help us understand mood or character?Well, let's break it down to the insult.Biting your thumb today may not seem like a big deal,but Sampson says it is an insult to them.If they take it so, it must have been one.This begins to show us the level of animosity between even the men who work for the two Houses.And you normally would not do anything to someone unless you wanted to provoke them into a fight,which is exactly what's about to happen.