I don't understand it.

• home is higher elevation by a bit
• I'm pumping harder in the mornings
• I like my job and have no dread about it
• ride home has stop signs and stop lights at the bottom of the biggest descents

...and yet I'm consistently getting better time going home.

The only factors I can think of are: heavier traffic going to work, so longer waits at stoplights, I'm more warmed up from spending 9 hours sitting in front of a computer screen?

Thoughts?