Without happiness, there isn't much point, but with happiness alone, we might as well be drug addicts or alcoholics (If these produce happiness!)
Don't we sometimes feel uncomfortable because we cannot understand, or we think we understand something, but we are wrong? So doesn't understanding as meaning also affect how we feel.
Understanding also means the ability to do. You cannot understand about cars if you can't drive them or repair them. If we want to be happy, we need to know how to become happy. We need to know what techniques are required to increase our personal wellbeing when things aren't going quite as we would like them to go. For instance, if we have to give a speech and we feel bad, we need to learn how to change our feeling so we feel good. We need to know the skill of changing how we feel. Understanding, therefore, involves:
Can you recall wondering why something happened, and even getting upset about it, only to feel better later when you realise you attributed the wrong meaning to it? Have you ever wondered what on Earth you could do, but later gained the knowledge to do it? And have you ever thought that something could not be changed then learned the skills and abilities to make the changes you wanted?
Do you see how understanding affects feelings too? And have you noticed that when we feel enthusiastic and happy we are more confident about finding out what we need to solve our problems.
Wellbeing and Understanding are clearly important and are closely linked together. However, have you ever known people who know what needs to be done, yet don't seem to know how to do it? Or they know 'what' but they do not know 'how' in the worldly sense.
Even though Wellbeing and Understanding are essential they are not the whole picture, because without Effectiveness a key aspect is missing.