Angryjohnny wrote:
1. It is the oldest annual marathon.
2. It has name recognition among even non-runners.
3. It is as American as apple pie, baseball, and the 4th of July.
4. You have to qualify to get in (I'm ignoring the charity exceptions)
5. The hundreds of thousands of people who come out to cheer you on and give you water, beer, oranges, etc.
6. The people of Boston. They have a reputation for being an unhappy lot but during marathon weekend they are hospitable and gracious.
7. From the rolling hills in Hopkinton to the left on Bosylton, I find the course to be beautiful.
8. It's the only spring major in the US.
9. It has a very deep field of serious recreational runners so you have other people to run with.
10. Boston is pretty easy to get to for most Americans.
11. The jacket and other merchandise with the ubiquitous unicorn logo.
12. It is a well-run event.
13. Boston is a cool city with lots of stuff to do.
I could go on.