give him an inch, and he will take a mile

podej mu prst a utrhne ti celou ruku
"I gave Billy a bite of candy and he wanted more and more. If you give him an inch, he'll take a mile." (Já jsem Billymu dal ochutnat cukroví a on chtěl víc a víc. Když mu podáš prst, on ti utrhne celou ruku.)