If you prized my lady’s favor at anything more than contempt, you would not give means for this uncivil rule (2.3.)
Malvolio is very rigid and conservative, and he does not approve of drunkenness, singing, or joking around.
He sees this type of behaviour as reflecting poorly on Olivia’s household, and he holds himself and the other servants to a very high standard.
This quote shows Malvolio behaving like he is better than other characters, and explains why they would dislike him and seek opportunities for revenge.