What is a happiness?
First define what does it mean to you, describe the current state. Are you happy? How to measure it? What is your metric of happiness? A number of smiles per day? A number of sunny days per month? Define the metric and measure it! Do you have data? - good. Now look for the root causes - what/who makes you happy? Create the list and concentrate on the one you have impact on. Look for a correlation between root cause and happiness - the positive one!
Define 2-3 root causes that have impact on your happiness and plan the future state: improvements related with the root causes. After it's implemented measure your happiness again just to make sure your process has improved!
Lean Six Sigma is simple: Define, Measure, Analyze, Improve & Control.
And btw: is a smile the metric, effect or maybe the root cause of the happiness?
Is happiness our own decision? Is it in our control? Is it stable?
The happiness is always now!