Pills and Bunnies

So this is random but I was thinking, what was the point of the machines taking over??? I mean what did they benefit from it? Since they don't have emotions, besides the exception of Agent Smith, where does the desire of self-preservation come from? 

I mean the only reason we don't walk around like "The Happening" is becuz we have attachments to things here; ie. Love. Our attahments are extensions of our love, which are emotions. But to be a machine or a computer u are like a animal or "angel" (in the Islamic sense) for that matter. You just get your command and execute.

So I feel like I missed something. What y'all think?