You’ll accumulate a lifetime supply of safety pins (used for attaching your runners’ bib to your shirt or jacket and available by the handful when you pick up your running packet prior to the race).
You’ll have plenty of content to continually post on Facebook, Instagram etc. (pictures of you crossing the finish line, pictures of your medal etc.).
You’ll never run out of topics to discuss at any social event (even if the non-runners aren’t interested since they all think you’re crazy anyway).
Bananas, bananas, bananas (after run necessity).
You get to hang out with other people who are just as crazy as you are.
You have a chance for a podium finish (first second or third in your age group). See 2. and 3. above.
You’ll always have a closet full of t-shirts to wear.
You’ll have plenty of bling to decorate your office (medals to hang, bibs to pin up, trophies for your desk).