I don't have a link to the source anymore, but the quote below was taken from an article published in a local paper almost 2 years ago:
...almost 40 per cent of people in a Statistics Canada study reported they actually enjoy their commute [by car], as long as it’s not too long. The number leaps to 59 per cent for cyclists (another reason for motorists to hate them) and 46 per cent for walkers. It plummets to 23 per cent for public transit users, mostly because it takes longer. When commuting times are the same by train or car, people reported the same satisfaction levels. Those who liked their jobs were also happier commuters — 64 per cent said they liked it.
So, other studies have shown that bicycle commuting does indeed have a higher satisfaction rate than by car or bus/train.