When you run a mile or something and then a "runner" or as I like to call them "crazy, insane person" says to you, "oh my god. congrats. you should TOTALLY run a marathon with me!"
Just because you want to be nuts and destroy your body in a marathon doesn't mean I want to. When someone says to me, "I just ate a hamburger" I don't scream out, "oh my god, you should TOTALLY come kill a cow with me!"