The Irony of "Happiness"

I was watching the iconic movie The Matrix for the first time a couple of days ago when one of the characters made a remark about the limits of human happiness that really intrigued me. Agent Smith, the antagonist in the film, explains to the protagonist, Neo, that the human race was miserable despite the fact that they were living in a perfect utopia: "Did you know that the first Matrix was designed to be a perfect human world, where none suffered, where everyone would be happy? It was a disaster... Some believed we lacked the programming language to describe your perfect world, but I believe that, as a species, human beings define their reality through misery and suffering." While I don't believe that suffering defines human beings, I do think it plays a very big role in one's quest for happiness (or rather contentment, as happiness is just a temporary feeling whereas contentment is a constant feeling of satisfaction). It is very hard not to grow accustomed to the things around oneself and take them for granted. After all, it is human nature to be greedy and always desire more than what is given. This makes being grateful for what you have exceedingly difficult, as one must be constantly grateful for what they have. The majority of people only realize how great things once were for them once they no longer have them. So while I think that suffering does not define the human condition, it is essential to remind people about all the great things they have in their life, for those who are truly happy are the ones who are content with what they have.