If you investigate within, moment by moment, you will see that the tense way is anger, the way of sorrow. Going this way there is only difficulty and distress. Indulgence in Pleasure - if you've transcended this, it means you've transcended happiness. These ways, both happiness and unhappiness, are not peaceful states. The Buddha taught to let go of both of them. This is right practice. This is the Middle Way.
These words 'the Middle Way' do not refer to our body and speech, ...they refer to the mind. When a mental impression which we don't like arises, it affects the mind and there is confusion. When the mind is confused, when it's 'shaken up', this is not the right way. When a mental impression arises which we like, the mind goes to indulgence in pleasure - that's not the way either.
We people don't want suffering, we want happiness. But in fact happiness is just a refined form of suffering. Suffering itself is the coarse form. You can compare them to a snake. The head of the snake is unhappiness, the tail of the snake is happiness. The head of the snake is really dangerous, it has the poisonous fangs. If you touch it, the snake will bite straight away. But never mind the head, even if you go and hold onto the tail, it will turn around and bite you just the same, because both the head and the tail belong to the one snake.
In the same way, both happiness and unhappiness, or pleasure and sadness, arise from the same parent - wanting.So when you're happy the mind isn't peaceful. It really isn't! For instance, when we get the things we like, such as wealth, prestige, praise or happiness, we become pleased as a result. But the mind still harbours some uneasiness because we're afraid of losing it. That very fear isn't a peaceful state. Later on we may actually lose that thing and then we really suffer.
Thus, if you aren't aware, even if you're happy, suffering is imminent. It's just the same as grabbing the snake's tail - if you don't let go it will bite. So whether it's the snake's tail or its head, that is, wholesome or unwholesome conditions, they're all just characteristics of the Wheel of Existence, of endless change.