There are varying degrees to desperation I can see. There can be any reason for that desperation. Despeartion can be of anything.
What does a person do when he/she's desperate? Try something that's really off hand!
Come up with things which that person hadn't dared to do.
Or simply drown oneself in misery and drink to death.
Desperation can KILL.
Desperation can RESURRECT.
There are many tales when characters gain a major epiphany through desperation.
Times when these characters are on the brink of total collapse.
Desperation can create never thought of confidence yet desperation if not controlled can be self-destructive!

WHY am I writing this?
Well, on an off hand comment, desperation can lead to something good..The toughest part is hanging on while in the phase of desperation.

AM I speaking this in terms of my experience?
Well, NO to be precise. But as I can see, everyone's desperate in their own ways. We just don't see it. Desperation is to mankind as happiness is to mankind. It's common!

WHY desperate?
Money, girl, fame, gadget, acknowledgement, acceptance. It can be anything. The need for human soul to feel complete varies widely but there's always that itchiness for something that " wish would have been true".

So..
There's really nothing one can do that much as to just control and live with it. Life's one hell of a FORGET-and-MOVE-on thing, so GET USED TO IT. If you were born with three-nipples, maybe that's just the way it's supposed to be. Being DESPERATE really does nothing.