I believe it's more a mindset than a journey. For people who are depressed, I believe all the treatment done just brings them back to where they originally should be. As after been cured some still have the tendency to relapse if they don't hold on to happiness has a reality that occurs in the mind.
It's not a journey as people who work hard and eventually achieve success or get rich sometimes still feel they need more happiness. Happiness is an existing now. The earlier we realize it, the better for us.
The fixed formula of been happy is to first realize nothing can truly make happy until we chose to be contented with what we already have and not placing or tying that special feeling to someone or to a thing.