We start off with a complete letting go of our concerns of our body or mind - as if we are on a paid vacation with no obligations. This helps us get into an exploration of what it means to be happy. Not the momentary happiness that leads into disappointment or frustration but the happiness that is longer lasting.
Anger is the same to all of us, sadness too but somehow happiness has a personal definition. Maybe peace is a better word; less controversial. Eventually, we are looking for the same!
Happiness is being OK with what we have and what we don't have. The projection of what is missing in the future (with the promise of bringing rest and peace) is the cause of unhappiness!