Great in the Godfather.
Sollozzo: If you're worried about security for your million, the Tattaglias will guarantee it.
Sonny: Whoa, now, you're telling me that the Tattaglias guarantee our investment without...?
Don Corleone: Wait a minute.
[the Don gives his son a cold stare, freezing Santino into silence. The others fidget with embarrassment at this outbreak, but Sollozzo looks slyly satisfied...]
Don Corleone: [dismissive] I have a sentimental weakness for my children and I spoil them, as you can see. They talk when they should listen. Anyway, Signor Sollozzo, my no to you is final. I want to congratulate you on your new business and I'm sure you'll do very well and good luck to you. Especially since your interests don't conflict with mine. Thank you.
[Sollozzo leaves]
Don Corleone: Santino, come here.
Don Corleone: What's the matter with you? I think your brain is going soft with all that comedy you are playing with that young girl. Never tell anyone outside the Family what you are thinking again. Go on.