In no particular order.....
1.This is strictly a hypothetical consideration: Although you would love the acclaim and success,you would not take a 10 year career of national championships that concluded with no further running of any kind OVER a lifelong ability to run. You like to compete but the prime motivation to run is your consuming love of the sport and the feeling you get while taking part in it.
2.You don't need to be with others to enjoy running. Sure, you enjoy the social aspects of running with friends on those easy Sunday 20 milers,but,you can enjoy it just as much running alone. I have known lots of runners over the years who've had a difficult time getting out there for any kind of running without having someone along with them.
3.You run without using an Ipod and earphones, you don't need them, in fact,you look forward to the quiet of a run. The reality of #'s 2 and 3 is that,to you, running is never boring.
4. You don't need to examine your shoes to know when it about time to get a new pair. Maybe this one means you've just been running for a long time but I thought I'd put it in anyway.Perhaps this exemplifies your preoccupation with running.
5.When you wake in the morning you already know where, when and what kind of run you'll be doing that day. With a holiday or special occasion coming up you make it a point to schedule a run ahead of time to fit in with the festivities.
6.As you get older you continue to run(and race) despite diminishing speed and performance. I know runners who have quit after reaching a certain age and their per mile average slowed.
I agree with the great Jack Foster when he said, and I'm paraphrasing here, "I don't feel as if I'm running any slower as long as I don't look at my watch." If you love to run,what's the difference between running 6 minutes or 9 minutes per mile?
7.You continue to run despite others telling you,you should quit. You've just had your third meniscus surgery and the Doctor,your wife and friends tell you it's time to hang it up. This is not even a consideration because you know that it was a simple reparative surgery, it wasn't like you had a knee replacement or anything.
The bottom line, a life without running is something you don't even like to think about.
8.This is kind of related to #7, you've tried other forms of physical exercise but none give you the feeling or enjoyment like the one you get while running.
So how do you truly feel about your running?