Not everyone runs for the same reason.
Some people run because they enjoy it; some people run because they need to de-stress; some people run just to get away from their annoying housemate and the piles of unwashed dishes.
Whatever your reason for running, it's important to remember that it's no less valid than anyone else's. Your 5k weekend run to shake off the work-week's cobwebs? Just as important as the seven marathons that girl in the office keeps banging on about.