Cause of Procrastination

what is the basic cause of procrastination?  I am interested in hearing well thought out ideas and responses from all of the users on this great site.  it seems to me there may only be 3:  Laziness, fear and a lack of trust.  the first 2 are kind of universal as issues in all kinds of problems and addictions and have been addressed @ length.  But I have never seen anyone address the lack of trust.  

There is an article on demand resistance on this site which I think is another term for wanting to retain control.  When you ask me to do something, anything - or even if I ask myself to do it - I have control, the illusion of control as long as it is not done! Once it is done I lose that ability for self delusion.  Foolish, childish, dysfuntional,etc, but it serves a very primitive purpose.  The question is why someone would want to maintain control in such an irrational and self defeating way.  The answer is always some sort of lack of trust.  If I trust the requester, myself, the world, other people, my parents, G-d, any or all of the above; then I am willing to relinquish control. More to the point, I feel no need to have control in the first place. 

We can always trust ourself.  Our ability to make decisions - the more we trust that gut feeling, that instinct, that voice that says "I am comfortable with this minor (or major) decision" the more that voice is active and informing. 

In short the way to trust one's self more is by trusting one's self.  And then... well we will all be lazy occasionally and all have our fears once in a while too.  But it will eliminate the vast majority of the compulsive procrastination. 

what do you think?