This happens to me on occasion in "everyday life," as I tend to use big cameras which do not lend themselves well to being kept in a pocket for any moment. That is why some serious photographers will carry a small P&S in addition to their SLR; unfortunately, I can't get over the issue that buying a P&S would take away money that I would have used to get another lens for my SLR, so I just accept the compromise that there will be some shots that I will never get.