When a person should be spoken with, and you don't speak with them, you lose them. When a person shouldn't be spoken with and you speak to them, you waste your breath. The wise do not lose people, nor do they waste their breath.
When you serve your mother and father it is okay to try to correct them once in a while. But if you see that they are not going to listen to you, keep your respect for them and don't distance yourself from them. Work without complaining.