Whenever I hear that phrase, I usually get images of an American asshole that overworks himself and other people because he doesn't know how to relax. But he believes he's the shit and thinks everyone is lazy or just needs to work harder at everything to enjoy life and/or get what they want. So "Work hard, play hard" ends up being their slogan for a perception of laziness and failure/inadequacy as coming from those that 'take it easy' or 'pace themselves'.

I'd much rather "work smart, play more". But I guess that wouldn't make most people feel like they are doing what they should be.