give someone an inch and they'll take a mile

saying

said about someone who has been given a small amount of power or freedom to do something, and then has tried to get a lot more

得寸进尺

I have a colleague who always wants more than what has been given. Give him an inch and he’ll take a mile.

我有一个同事，他总是想要比别人给他的更多。得寸进尺说的就是他。