But honestly "happiness" means different things to different people. I guess you could say that happiness is relevant. I think that the word "joy" is the emotion that I strive for most. It is more like a state of being actually than an emotion or feeling. We can feel joy even in the hardest trials if we choose. But it sure is hard to be happy when it feels like life is raining on your parade. Joy is found deep inside and it is a choice. It should be the life theme of a Christian--to be a light to a world living in darkness and pain. Instead of asking "why me?" when things go wrong, I say, "why NOT me?" What makes ME so special that bad things shouldn't happen to me? :-) Accept the hardship and feel the joy in the midst of it. It's simply a matter of perspective. If we lack joy we can always pray for it!!
Consider it pure joy, my brothers and sisters, whenever you face trials of many kinds, because you know that the testing of your faith produces perseverance. Let perseverance finish its work so that you may be mature and complete, not lacking anything. (James 1:2-4)
And we know that all things work together for good to them that love God, to them who are the called according to his purpose. (Romans 8:28)
But I still really love the John Lennon quote too!! :-)