Insight to being married to a runner

It was just brought to my attention that some browsers are now allowing this comic to be seen in full-screen. I'm sorry, the captions are:

"What happened to you?"

"well, I was going to go just 3 miles but it's such a nice spring day I stretched it to 10 miles!"

"Don't get angry, you know you married a serious runner."

"I know, but you were only going outside to get the MAIL!"

"Oops...it's still outside."

(Story of my life!)