There were 5 ancient Greek philosophies of happiness

At the risk of gross oversimplification, there were five Greek philosophies of happiness.

• Socrates - only the poor, those who have nothing to lose, can be happy.
• Aristotle - you have to be born rich to be happy (in reality healthy, wealthy, good family, good friends).  Aristotle's Nichomachean Ethics introduced the good life.
• Epicurus - remove all causes of pain to be happy (don't spend time with irritating people or doing annoying things). "Pleasure is the absence of suffering".
• Stoicism - life is about suffering. Happiness is to accept the obstacles with serenity.  Stoicism was founded by Zeno of Citium.
• Hedonism - happiness is spending time doing what gives you pleasure. The basic idea behind hedonistic thought is that pleasure is the only thing that has intrinsic value. 

In reality, the ancient greeks had no word that exactly matches our current word "happiness".  The closest term from their language was Eudaimonia.  Aristotle says that eudaimonia means ’doing and living well’.  What is interesting to me is that I view happiness as a state - but the greeks had no word that represented a steady-state happiness - only an active form of happiness that required behaviours in line with a set of virtues.

Some useful resources:

• Psychology Today article on The Pursuit of Happiness
• Gretchin Rubin on The Happiness Project Modern readings on happiness, Classic reading on happiness
• The 90/10 rule - how to mess up a perfectly good day
• My most-visited-ever blog post 17 daily habits for a fulfilling life
• Aristotle's Nicomachean Ethics at Google Books