For example, commuting has been instrumental in helping me lose 35 kg in 10 months, from size 46 to size 36.
I made the decision to always commute walking (30 minutes commute which I do 4 times a day because I also wanted to have lunch at home with my family). Once you factor in that your commute is 30 minutes instead of 10 minutes (or 0 minutes if you work at home), things are rather easy.
So I end up spending 2 hours a day walking, which turns out to be an activity that I happen to like a lot (its been a bit of an evolution, possibly inspired by the "Love what you do" approach to things as opposed to "Do what you love") and therefore I do not see it as a time waste at all.