Never been to CO personally, but friends say if you aren't into outdoor activities/slow lifestyle, it can be dull. A lot of social groups are centered around what you do outside.
I've seen this before, but never quite understood what it means- lack of a 'night life?'
However the positive is the people in CO are the fittest in the nation due to this love of the outdoors.
So I asked somebody in a store if there was a race or something.
They looked at me funny and, no, it's just Saturday in Boulder.
Work seems to go slower here. It seems even the frantic pace of startup life takes a back seat to work life balance.
People aren't usually in a hurry on the sidewalks downtown. It can be infuriating if you have somewhere to go.
But if you are used to high stress and crappy work/life balance (or have adapted to that lifestyle) I can see how it would try your patience.