For anybody who doesn’t know or remember, Chuck pulling his ear is supposed to be a sign that he wants to end dinner, except Jimmy is so funny that Rebecca doesn’t even notice
I actually completely understand Chuck's awkward discomfort here because yeah it feels kind of hurtful when your brother and wife make jokes at your expense basically and your brother is making your wife laugh more than you did but I think he took it too hard because he could have just joined in, it's better to laugh at yourself with people than sit there and let them laugh at you
Thing is the people like Chuck would rather keep that internal discomfort in than learn to be more connecting towards people like its a strike at their pride and status
This scene actually shows us exactly why their marriage failed. Its easy to assume that Chuck probably hasn’t made her laugh like that for a long time based off his reaction, she was clearly amused by Jimmys charismatic and whacky personality which would tell us thats obviously the kind of guy she prefers. Not someone boring like Chuck
Theres also the fact that he is ashamed of his working class roots. He prides himself on his manners (following the social contract), going to university, getting a degree, appreciating the finer things, having a prestigious law firm and a upper class wife only for her to instantly warm to his scumbag brother who makes jokes about his profession, brought beer, drinks it out of the bottle and is so unashamedly himself.
And also the root of his pride and issues with Jimmy. He expected her to smile and begrudgingly go along with Jimmy’s jokes, but instead she genuinely laughed and fell under the same spell as everyone else.
