I started to walk to work more than a year ago (5km one way, about 45mins). Makes a world of a difference, as it gives me more or less two hours of exercise per day, time to get my mind on/off of work, call family/friends and other stuff. Bottom line for me - it's less the time spent commuting, than whether you can spend it in a useful way.
Not to compete, but a 2013 study found bike commuters to happiest. Walkers were #2. :)
http://www.outsideonline.com/1795631/study-bike-commuters-ar...