Here is an important notion - do you have free will?
The answer is no.
My interest in this has been rekindled by finally finishing war and peace - there is a long piece at the end and how history is made and whether individuals who make history are acting through free will or through necessity. In this case, necessity is another way of expressing causality - if that happens then this is the response. Theoretically if you could work all the contributing factors to a particular moment in your life then you'd know what would happen next. This is impossible in reality but it's a nice theory.
So, to cut a long story short, we are programmed by the conditions of our life to behave a certain way. This programming comes from all different directions but the most worrying is the conditioning we receive from the media and entertainment - mainly because we have a tendency to believe anything we hear. This makes us behave in a certain way that we are almost powerless to control. I think that will do for now - I don't want to get too political.
When we act or think a certain way, we might like to reflect on why we do so. It is not our thoughts, but the way we have been conditioned. Now, we might further realise that because we are not really the owner of our thoughts, we might wonder who we are. And from here you can glimpse what freedom might actually be - which brings us back to feeling good and happy in some bizarre way.