Give him an inch and he’ll take a yard.
More Traditional Proverbs:
If you're going to live by the river, make friends with the crocodileTraditional
Like a hot house flower.
Traditional
Physicians' faults are covered with earth, and rich men's with money.
Traditional
Make like a tree and leave.
Traditional
The wise adapt themselves to circumstances, as water moulds itself to the pitcher.
Traditional
Not for all the tea in China.
Traditional