The curse of expectations

I have a full grown labrador which is blind by birth. Surprisingly, he seems quite unperturbed by his shortcomings and happily keeps bumping into things. I wonder if he would remain so unconcerned by all this, if he were a human.
Is our power of thinking a boon or a bane?
That may be a radical provocation, but I have noticed that we humans have made our lives miserable by our expectations. If only we could live by what is, rather then what would be or could be! The irony is that the future remains mostly unaffected by our expectations. Remember the old saw - Half the things I worried about did not happen and half the things that happened were not seen by me!
There is a sensible concept of randomness, which explains all this. In any case, how do we know whether whatever is happening is good or bad for us? Remember the case of some people in New York who got delayed in traffic on 9/11? Well, the delay saved the lives of some of them. Equally, it might have caused some of them to be in the wrong spot at the wrong time.
Expectation also seems to directly insult our concept of God. Why refuse what HE has granted to us? Do we profess to know our needs better than HIM? Once I did hear something nice like - You are not what I had prayed for, but obviously you are the answer to my prayers.
Does such a philosophy make us lazy, aimless and adrift? Well, my labrador seems quite active, bumping into one thing after another.
Indian philosophy ( Geeta ) has good practical advice when they tell us to ' Do your duty, but do not get attached to the result'.
Never complain of anything, not even the weather. Nothing matters to the man who says - Nothing matters. The problem is not in the event, it is in it not coming up to our expectations.
What is, is.