If you needed that scene to understand that Joffrey is a sociopath then I dunno what to tell you. They've pretty much made him a cartoon villain. At this point I wouldn't be surprised if he tied Sansa to a railroad track (they exist in Westeros) with a top-hat and monocle and cackled profusely. I don't see how the scene is development if it's everything we'd expect from the character.
And Joffrey told the whores to go back to Tyrion and show him what he did anyway. If we actually got a follow-up then we'd see Tyrion put him in his place, but I really doubt they're going to follow the scene up since it was an added-for-TV scene with no effect on the plot.
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No amount of planning will ever replace dumb luck.