Everyone knows someone who is running the marathon this weekend, or who did it once, or who always talks about doing it and one day might. It's a huge buzz just to be there and to witness the extraordinary levels of human effort on show as people run to the finish line.
But not everyone has to do it. Some of us just don't really want to run 26 miles in front of lots of strangers. Here are 21 good reasons why you're not running the marathon this Sunday.
1. You're quite fond of your toenails.
2. You did a 10k once, and it was horrible.
3. You did another 10k, just to check, and that was horrible too.
4. Runners get weird invisible injuries that take months to heal.
6. What if you needed a poo half way round?
7. Sports bras. You have to choose between protecting the girls from gravity or being able to breathe. These are both important things.
8. Sundays are for sleeping.
9. You didn't get in on the main ballot, and are pretty sure you would struggle to come up with the huge amounts of sponsorship needed for a charity place. Your friends love you, but not that much.
10. The training schedule would seriously scupper your social life.
11. And there's the not-drinking thing. That's some massive commitment.
12. You are not built for running.
13. You have dodgy knees.
14. You have dodgy hips.
15. It would be embarrassing to stuff it up and drop out after 5 miles.
16. Your friend is doing it and she needs your support.
17. Swimming is much better exercise anyway.
19. And dancing. Dancing is good for you.
20. You are slightly curious though, how it would feel to be one of the ones wrapped in a silver blanket, hobbling and beaming, with a medal round your neck.
21. There's always next year.