I do 20 very hilly miles one way in the morning but take public transportation home in the afternoon because I have to pick my daughter up from daycare but before my daughter was born I did the commute round trip most of the time and it does get to be a bit of a drag not because the riding isn't fun, but just because I have stuff to do in the evening and stacking a 4 hour commute on top of a 10 hour workday doesn't leave a lot of time for much else.