I love the story of how Ray Anderson and Interface turned the perceived cost of a solar energy system into a new product: Solar Made Carpet, and promptly sold enough of the new product to cover that cost many times over. It reminds me of a story that Gunter Pauli, founder of ZERI, told me about when he was CEO of Ecover. He wanted to build an "ecological factory" but the banks wouldn't lend him the money. For whatever reason, they would lend him money for a major branding/advertising exercise. So he took the money, built the factory and said "tadaa - there's our advert!". Gunter's a bit like that - a big man brimming with self confidence, enthusiasm and a contrarian nature - your bank manager's worst nightmare, but great fun over a couple of beers.
When I talk about positive thinking, it's not some new age-y "believe in it and it'll happen" fluff. What I mean is looking for solutions rather than problems. If you said to Gunter "we've got this acidic waste stream that's a problem" - he'd be straight back at you - "that's not a problem, it's an opportunity - what could you use acid for?" Diageo made a similar paradigm shift recently - instead of "treating" their wastewater at their distilleries, they're using it as a source of energy via anaerobic digestion.
The great thing about this kind of thinking is it enthuses everyone. From the layman to the biggest seen-it-all-nothing-impresses-me, there is nothing that will grab their attention like some examples of problems being turned into solutions. It really fires up workshops as people hunt for similar breakthroughs.
So next time you see a problem, whether technical, physical, societal or economic, why not take a step back and say "how can we flip this around into a solution". You may surprise yourself.