I always just assumed that "you didn't know what you'd get" meant that when the chocolate box gets to you only the shitty ones nobody likes are left. There is a

I always just assumed that "you didn't know what you'd get" meant that when the chocolate box gets to you only the shitty ones nobody likes are left. There is an alternative in my country which is "Going out is like a box of chocolate, if you wait too long there are just a few disgusting alcoholics in the corners left".