you can't make an omelet without breaking eggs

proverb Sometimes, you have to do unpleasant things in order to complete a task or meet a goal. Your students clearly don't respect you. I know you don't want to yell at them, but you can't make an omelet without breaking a few eggs. If I don't cut people's salaries, the company is going to go bankrupt. It's unfortunate, but you can't make an omelet without breaking eggs.

To accomplish something, you have to be willing to make sacrifices. This term is a straight translation from the French (On ne saurait faire une omelette sans casser des oeufs), who not only invented omelets but transferred the term to other affairs. It was translated into English in the nineteenth century. Combining two clichés, General P. Thompson said, “We are walking upon eggs, and whether we tread East or tread West, the omelet will not be made without the breaking of some” (Audi Alt, 1859; cited by OED).