So I just read a WSJ article called, "No Satisfaction: Why What You Have is Never Enough".  The article poses two reasons:

     1) We aren't built to be happy. Rather, we are built to survive and reproduce. 
           -or-
     2) We're bad at forecasting.   Experience should help us avoid repeating such mistakes. But it doesn't, in part because we don't accurately recall how we really felt.

I have a 3rd theory (and theories are like excuses, which are like, well, you know the saying).  I think that Bandura had it right.  Social Learning Theory works a bit too well.  We see someone else with something and imagine that having that something will give us all of the advantages we imagine the other person has.  We put other aspects of our lives on hold - including things that could actually make us happier - until we achieve the object we imagine will fix all of our problems.  I think we all know people who have put off taking a vacation until they look perfect in a swimsuit, or take on crippling payments in order to drive a certain car, or pass on hanging out with their real friends so they can play golf with the boss in pursuit of a promotion.  We are like Wile E. Coyote chasing the Roadrunner; it doesn't matter how many cliffs we fall off, how many anvils drop on our heads, or rockets explode in our faces, we remain in hot pursuit.

Am I immune?  Aw heck no.  We have the day off today, so where am I?  At my desk in my office, of course!