What I can't have

Why is it I want what I can't have, or perceive I can't have so badly?    I am pretty contented most days but once in a while I get in my head I want something badly.  The less likely is it I can have it, the more likely I am to want it bad and work hard until I find a way of attaining it.  Some things I just can't have though, I just can't and it tries my moral fiber.  It is better to not have, than to have gotten by ill means.  It is better to not have, than to have by false pretenses.  It is better to not have than to have simply because I want. I want to earn what I have, I want to deserve what I have and I want to get what I have by genuine expression.  I want you, for me, but I only want you if you really like me for what I am.  This is the most painful realization and rejection to the utmost.  Realizing that someone you care about deeply doesn't care for you at all.  But this reality is far better than the reality of being bound to someone who has loved you under false pretenses.  I love you for who you are.  Whether you spit on me, shit on me or quit on me, I still love you even if it's nonreciprocal.  When you feel unloved, know it's not so, even if it is from someone you do not care for.