Although happiness depends to some extent upon external conditions, it depends chiefly upon conditions of the inner mind.
Our daily habit of meditation gives us control over the contents of the mind. Just our practice of concentration - which precedes the peace of meditation - allows us to let thoughts fall away which are not useful. We bypass recrimination about past events and avoid wasting energy by worrying about the future. We gain the mental strength to retain equanimity when events do not go as planned, and can learn from this helpful feedback. In the depths of meditation we reach that true happiness which we call bliss and experience as our own inner nature.