Smarts + Persistence = Getting What you want

A small boy is sent to bed by his father.

Five minutes later.....'Da-ad....'
'What?'
'I'm thirsty. Can you bring a drink of water?'
'No, You had your chance. Lights out.'
Five minutes later: 'Da-aaaad.....'
'WHAT?'
'I'm THIRSTY. Can I have a drink of water??'
' I told you NO! If you ask again, I'll have to smack you!!'
Five minutes later......'Daaaa-aaaad.....'
'WHAT!'
'When you come in to smack me, can you bring a drink of water?'