Pretty much everything mentioned here, and especially the "sense of purpose".

I also love the feeling of being sneaky and "cheating the system" since I live very close to a bridge which can take 15 minutes to get onto by car in the morning, and only 3 minutes by bike.

I love laughing at people stuck in traffic jams, strapped into their seats like prisoners listening to propaganda and commercials on the radio.

I love that I've lost 3 inches off my waist and have the energy of a kid again.

I love crossing paths with other commuters on the way home who probably feel the same way as I do.