finish what you started?

So my friend, who has played and loved soccer for 15+ years, is finally finishing his career. He's played everything from travel leagues to NCAA ball. Yet somewhere along his line, poor coaching and team mates letting him down took the fun out of the sport. He says that the decision to leave soccer is definitely a burden of stress off his shoulders.

Yet people give him crap like:
"Lace em up and hit the field pal. If you don't you will regret it for the rest of your life."
and
"No.... it's about finishing what you started."

What exactly did he start? I'm sure when he first began, it was because he enjoyed it. I doubt he signed a contract with himself that said he would play soccer for X amount of time, and only then would he be finished. While there's much that can be said about commitment and dedication, it's a game. When you play, you don't have to make a choice to assign your destiny to the whim of the sport. There's so much out there that could be better, and he's finally accepting that he may want something else. And people call him a quitter.