Have you ever done something really, and I mean really, out of your comfort zone? High heights have always been one of my biggest fears.  I went to Paris and didn't even consider going up in the Eiffel Tower if that gives you perspective on how crippling it's has been for me. That being said, I've become fairly adventurous as I've gotten older which has worked out in my favor when I've been faced with heights. Hiking, for instance, is one of my very favorite activities now and it has really helped quell that acute...