do not know what is really important, have not learned much about life If you refuse the assistance, you don't know which side your bread is buttered on.
DON'T KNOW WHICH SIDE YOUR BREAD IS BUTTERED ON
Meaning of DON'T KNOW WHICH SIDE YOUR BREAD IS BUTTERED ON in English
English idioms vocab. Словарь английских идиом и выражений. 2012