Yeah, I don't understand the problem with using parkour as a verb, but everybody says, oh man, look out, that's bad... whatever.
That's great though. Nobody I know has ever actually tried. The excuses they come up with are great though. "Oh, all my strength is in my legs." (from a guy who obviously had no strangth) "ahh, I just got a bad grip on it." (said person couldn't even get part of the way over the rail) "It's too wet/slippery, I don't wanna chance it." (I just did it, it's obviously not THAT wet...)
I don't see the problem with just admiting that you can't do something. Why won't people just say, oh, yeah, you can do something I can't. I mean, if I'm sitting my some really smart overachiever kid in math, and he does some algebra problem in his head really fast while I've writtin down maybe half, I'm not going to say, oh, I coulda done that, I'm just too tired to think straight or something.....