Idiom Rock the boat

Source: www.sozoexchange.com

This is a phrase which means to go against the rules of a group. Let’s imagine that you are cruising smoothly in a boat, but suddenly the boat is rocked or shaken by something, you will probably feel uncomfortable or upset. This phrase also means to upset people who accept the existing condition.

For example, you can say, “Don’t rock the boat if you want to be liked by many people in this small and conservative village.”