At some point I stumbled across this very amusing video:
(check out some of their other videos, too - the Road Vs. Mountain bike rap battle is hysterical)
Unfortunately there's no How to be a Runner video in their series, because the road bike one got me thinking about who would be on the runner enemy list.
So far I have:
Walkers (especially the ones who line up at the front at races)
Nordic Walkers (why do they always stare like they've never seen a runner before?)
Pelotons (because of the one that almost ran me off the road on Northshore that one time)
Dogs (both the off-leash variety for being terrifying, and the on-leash variety whose owners don't clean up after them)
"You are going to ruin your knees" people (because shut up)
Who is on your enemy list?