Business cycle

Sometimes life is juz like the business cycle. There's boom, through, upswing n etc.
Boom- when u're happy
Through- when u're sad
Upswing- when u're about to b happy
Downswing- when u're about to b sad
Can we predict our future ??
Some say yes n some say no.
I feel is no.
Why can't we predict our future ?? Isn't it better if we can know the future n do some preparation b4 something happen ?
If everyone knows the future, I bet there won't b any sad ppl in this world anymore.....

How pathetic life is..