Does life have a rear-view mirror?

I was wondering whether it is always possible to know when you are at a crossroad or intersection in your life. It seems to me that there are certain times that looking back and seeing where you have been and where you're currently standing are the only ways of figuring out how things turned out the way they did. It isn't always possible to know or realize how the little choices or big choices will effect you now, or in the future. But the hiccup in my thought is that the aggregate of the little choices may turn out to have a bigger effect than one or two of the big decisions that we make. Make sixty little choices, and that can destroy a planet, but make one "Big decision" and that actually means nothing to anyone other then the person that did the decision.

Just have to keep from going mental about every little choice you make.