I remember well something said to me years ago by a laid-back friend – ‘It is hard to piss off a man who doesn’t give a shit’. I made the point in Survive your Camp that when you are in a difficult life situation you have to let stuff go. Use apathy as a defense.
But this has application to your life in general. The Buddha said that all unhappiness is caused by attachment. This could be attachment to possessions, to your job or avocations, or to people. Life is easier if you are not so attached.
Many people become quite disheartened when their comfortable life changes for the worse. They suffer bereavement, divorce or a loss of a job. You should be thankful for the good things you have, but realize that they are not permanent either. This realization will make their inevitable loss to you less painful.
This is an underlying ethos of stoicism. Stoics classify everything as either good, bad or indifferent. The only things that are good are virtues. You should work on improving these. The four cardinal virtues, from ancient Greek philosophy are prudence, justice, temperance (or restraint) and courage (or fortitude). The seven heavenly virtues of Christianity are chastity, temperance, charity, diligence, patience, kindness, and humility.
The only bad things are vices. The vices that mirror the virtues in Greek Philosophy are rashness, injustice, intemperance and cowardice. A fuller list of vices is the seven deadly sins of medieval Christianity - wrath, greed, sloth, pride, lust, envy, and gluttony. The seven virtues above are opposites of these. You should work at eliminating them.
Everything else is indifferent. Everything external to you, i.e. outside your total control, should be indifferent to how you feel. There are preferred indifferents, rejected indifferents and genuinely indifferent indifferents. It is important to neither be excessively pleased about the preferred or upset about the rejected indifferent events. If they are outside your control you have no reason to feel excessively pleased or displeased about them.
Obviously it is preferred to have a job, wealth, friends and a family. You would rather not have illness, poverty or enemies. But it is important to neither be too attached to the former nor too upset about the latter. Anything outside your control should not affect how you feel about yourself.
If you can maintain a stoical acceptance of the good and bad things that happen in your life you will have much more control over your happiness. If something is upsetting you ask yourself is it a result of your vice? If not don’t let it bother you. If you are overjoyed at an event ask yourself is it due to your own virtue? If not you should restrain your joy. Something that is the result of an action by another can easily be taken away.
You will have a much happier life if you learn to not give a shit about good things or bad things. Chill! Be cool like Zeno.
(Illustration of Zeno from http://poignantboy.wordpress.com/2012/08/27/stoicism/)