Nothing is constant but change. I do not think there is a truer statement when it comes to describing the Universe as seen by Man. And we play no small role in this change, as most change perceived by us is in fact brought about by us. We have to bring change - it is our default setting.
I've often wondered if there's a single factor which could explain most of our behaviour; I don't think there is any clear winner... But boredom and monotony come close to hitting the jackpot. Think about it: you have a job and you're not happy with it. Now let's try figuring out why you can't be happy.
Option A: It's shite. It isn't something you like doing or maybe you aren't good at it... Or better still, maybe you don't want to be good at it. Perhaps, you aren't realizing your potential (whatever that means)
OR
Option B: This is a far more interesting option. You're doing something you like, you're good at it and you're making a difference to the world around you. But you're still unhappy. If you aren't, wait another couple of months. You will be. We detest monotony, however happy it may be.
Oh, and that's why people travel: to escape the rut. It's also the reason why people always reminisce about their childhood - it's the time when you undergo the maximum change, ergo it sticks in your head. Monotony explains a whole lot of other things too... And I shall try to make a convincing argument here.
When we're toddlers, we're experiencing a world of change: we're learning to walk, we're starting to communicate and we're going through that endless list of firsts. Everyday seems like a new year. However, as we grow, the rate of change slows down and by the time we're in our teens, we've learnt quite a bit. Suddenly, new things are hard to come by. Luckily, however, we have this period called adolescence when the known world suddenly seems changed and different.
You know what I'm talking about: that stage in life when you don't know whether you're a kid or a grown-up, that stage in life when you don't hate girls any more and are doing stupid things to get their attention instead... Some folks get through this phase quickly too and things begin to stagnate: Enter booze, sex, cars, money and the real world.
Now, over the past few millennia, Man has struggled to make the world a vastly complex place. The more complex the place is, the longer it takes you to break the code... Thus, it can keep you entertained for a longer period! Sooner or later, you end up figuring out the rules and then you start reading the code... That's when it starts getting boring. It's like playing a game with cheats, over and over again. There's no fun in playing with 'God-Mode' on!
I believe that's why people get married. Because Life isn't challenging any more! I'm almost tempted to quote a highly sexist Charlie Harper here: "If you have someone to clean your house and do your shopping, and you get some action on a regular basis, the only reason you need a wife is if you have some sick compulsion to give away half your stuff." Well, I don't mean it in a Male-centric way, of course... I'm just commenting on the way Marriage changes our lives. You can go all holier-than-thou and tell me about the sanctity of love; I'll just show you a happy couple before marriage and then I'll laugh.
That's why Marriage was invented, I tell you! You have to be more responsible and accommodate a whole new person in your life. The game becomes fun again - someone has changed the cheats! However, this only brings me to the most important exponent of the theory - kids. Any family is changed when a child enters this world. And that is the brilliance of the scheme of things - this desire to change our lives keeps our race alive.
It is in human nature to change the people around us as much as we change ourselves. And that makes the game far more interesting! Changing something you do not have direct control over but can only influence and manipulate is far more challenging and hence, satisfying. I'm sure that the pride you take in your child's success far outweighs the pleasure you experience while celebrating your own.
Gradually, the children grow up and things slow down. But what do you know: retirement is here! That's change too, right? So you enjoy that for a while... and then there are grand-kids. Finally, you realize that there is only so much you can change. Thank goodness Medicine hasn't progressed far enough to let you experience this low for too long. Thank god for Death.
Who knows what change comes after that?