I dont disaggree, but let us not forget the fact that life isn't always meant for happiness. There are sacrifices that need to be done so "others" can be happy. For example, people in one empire or lets say country will be scared and UNHAPPY when another country is looking forward to invading them, so brave men will rise upon them and engage the enemy in battle so that the rest of the empire will stay safe and protected. That's the big point. Soldiers are not happy in battle as they see their comrades get annahilated in the face of the world. But they become heroes.
Look at the world around you, just imagine whether you can count the vast number of people working everyday.Employees stuck in annoying traffic happens everyday just for them to get into their offices to educate or feed their children who spent long hours in front of the TV, or the computer playing Halo, MOHAA, Age of Conan, and stuff. Then this children grow up and marry and live away from their parents who miss them. The parents will aggree to the marriage cause that'll make their kids happy even if it really hurts in their side as loving parents to be separated from their children. Get the point?
Remember, not everybody will be happy all at the same time as the rest of other human beings on the planet. Now if you are happy, many are not experiencing happiness at this very moment.So there are always givers and takers,its that simple. Some people just cannot resist this philosophy and they give up, they kill, they steal, and make lies. But whatever your destiny will be, you draw the map of your life. A decision you made yesterday can affect what will happen today. But showing happiness today, even in times of trouble is a wise and noble thing because that shows that you are optimistic, able to go through it.