I agree with you, life is wonderful and we must appreciate it.
About your question, there are things that we have to do to make other people happy even it means that we have to sacrifice our own happiness.
It is not about us after all, we have to be considerate about the feelings of others as well. :)
Well I know that but ... why don't we do the right things altrue we know in the back of our mind what these things are :/
Why don’t we do the things we know are good for us? But why?
Maybe, it is the lack of willingness to do such things.
There's a difference between knowing what we must do and the willingness to do it :)