I'll see your logic, and I'll raise you common sense
The baby just ate, it can't / must be full.
Me:Is it 'must' or 'can't'?
Student:It's 'can't'
Me:Why is that Pedro?
Student:Because babies drink milk, so he is not thirsty but probably hungry
Me:Pedro do you realize what babies eat?
Logic:A+
Common sense:FAIL