Usually I wince a tiny bit, thinking that they left off the .2, which sounds totally obnoxious unless you've run 26 miles and know that that .2 feels like the longest distance ever. It's the distance between you and your family, between you and a medal, between you and a cold beverage, between you and finally getting to stop running. Oh, and there's also the fact that at that point you've already run 26 miles and still have to keep going.
I don't tell them any of that though, I just tell them the truth, "Oh, anyone could run a marathon. They just have to really want to do it." I believe that 100%. Sure, that's not to say everyone should. If you're 95 years old, 8.5 months pregnant, a heavy smoker, and hate pain it might not be for you. That said, I really believe that if you want to run a marathon, you can.
I think it's like the old saying, "How do you eat an elephant? One bite at a time." You run a marathon one mile at a time. You set little goals for yourself. You distract yourself. You listen to music, you people watch, you count things, you zone out, you think about what you're going to do when you're finished. You make it happen.
Sometimes in my life I get in the terrible habit of looking at the elephant as a whole. I see it standing in front of me, totally massive, ominous, and formidable. Then I get overwhelmed and either break down and cry, yell at my mother and husband, or totally freak out that I can't handle it and am going to fall on my face.
I need to learn to treat my life like a marathon and take it day by day, mile by mile. I need to remind myself not to look at the big picture, but at the little tiny bites that seem like things that I can handle. Sometimes I need to distract myself or zone out. I need to reward myself for the little victories. (Maybe those days I could substitute the elephant for a Whoopie Pie?) Some days I might be able to tackle bigger parts than others, and that's OK. It's all a part of the journey.