The sense of unfullfillment

Life is not as simple as maths is what I have learnt over the past few months. 1 and 1 very rarely add up to be 2. You can do all that is within your control yet find that not everything in your life is the way it ought to be.
My life is fast turning out to be a story of unfulfilled dreams and wishes. A guy going steady in life and earning a decent living shouldn't have too many reasons to be dis-satisfied with life. But life has its own way of playing tricks on you when you expect them the least. All of a sudden I find my life in a mess. Is there anything that I could have done better? May be not. Just that I could have accounted for some unpredictability in my life. All along I thought I knew people around me very well only to find that human beings are so unpredictable that many a times they don't understand themselves, leave alone others. May be thats the reason why on occasions people act in a manner extremely contrary to others expectations. There are way too many variables in life to predict anything. And thats why I say maths is a little easier. In maths you know what the variables are. Life unfortunately doesn't give you that liberty