No. Happier people work smarter. ^_^
Already down voted by cool hackers, so perhaps I need to put some first-grader-level explanations. ^_^
The classical saying declares that 'the only hell on Earth is ignorance'. The description of stupidity is, in general,
'restricted, repetitive behavior'. Several studies says that what we call a luck is a matter of attention and awareness (Catch the moment! - you know). Stress reduces awareness, make people too narrow, too repetitive (defense mechanism). Now, try to recall an illustration from famous (among hackers) Alan Kay's lectures, where people digging for a treasure and they're doubling the effort instead of shifting to other place. And at last, but not least, especially related to silent down-voting - one can't see what one don't know - recognizing has this 're' in front of it. ^_^
So, happier people, which means less restricted, less repetitive, less self-limited, more open, more aware, more awake, with broader vision and greater attention, calmer and balanced yes, in consequence, work smarter rather than harder.