Problems with the lines - Issue 2

It is also mentioned:
(Direct translation)
If you are happy, you let a day go by. If you are sad or angry, you let a day pass by too. Why not then let a day pass happily?

That is to say:
Whether you are happy or you are sad - you let a day pass by. Considering that happiness is so much more enjoyable compared to sadness and anger, wouldn't it be an obvious choice that you should pass the day happily?

Problem:
Is happiness or sadness and anger merely a choice? There are two main conflicting ideas (which are not really very conflicting really) in the society. I will illustrate as below:

First on says that feelings (i.e. happiness, sadness, and anger) are emotion that HAPPENS to you and that you don't control your feelings. That is to say, if somebody makes you happy or a happy event occured, then you become happy and vice versa for sadness and anger.

Second argument states that feeling is pretty much predetermined by the choices you make. If you have a predetermined idea that something is a happy event - you will be "happily" influenced by the occurance of the event (which is really from statement one). Or, you can determine that something unpleasant that has happened as really a learning experience - you made a mistake and therefore you learn from it - therefore you reap some form of happiness from knowing that all is not lost and perhaps the experience has gained you more things than otherwise if you did not make the mistake. Or the other way is to give excuse for someone that has wronged you. For example: Somebody has cut your road on the highway - you think better of him and say that perhaps he was late for work, and you are happy that you gave way to him and made his day a better day.

Now the problem with this two arguments is that we are firstly assuming that happiness is either the ultimate end goal of everything in life (and we choose to view things in a way that would maximize happiness). Secondly, we are also assuming that happiness will be more productive/useful than anger or sadness.

I will start with the second problem first as it is easier to understand, and perhaps it will lay some foundations for the first statement.

Many times in life, we learn more things as we go through periods of sadness. We realize when we cry - the crazy thoughts that go through our mind, how reality flashes before our eyes - the massize amount of memories and truths that race through our heads. Sadness can sometimes blind our reasoning, yet at times sadness forces us to look at life honestly and not always walk on cloud nine. Some thing goes for anger, MOST of the time, we become irrational when we become angry, but if we can still be happy and peaceful about all the murders, rape cases, wars, and all manner of unrest in the world - I suppose we have reached a state where we are selfish and other people's welfare no longer concerns us.

Essentially one, we will flow on to the next argument. If happiness is the end goal in life and that a win-win situation cannot always be achieved, then whose happiness matters more when there is a win-lose scenario? (i.e. for me to be happy, you have to experience sadness - to which we see again, sadness isn't always better than happiness)

Then again, is happiness the end goal of life? A little philosophical - I will make a statement that goes like this. Satisfaction and happiness are two different things. Although satisfaction and happiness are closely related, and that one affects the other in some way, yet they are essentially two different things. Suppose that we think that happiness is the end goal of life and we run after happiness all our life (which is basically what almost everybody in the world does in some way or the other), will we be truly satisfied in the end of it all? If there is a scenario where you cannot get both (an area where reality always hits us hard), what is more important?