Julian Baggini in The Guardian:
Epicurus’s distinctive feature is his insistence that pleasure is the source of all happiness and is the only truly good thing. Hence the modern use of “epicurean” to mean gourmand. But Epicurus was no debauched hedonist. He thought the greatest pleasure was ataraxia: a state of tranquility in which we are free from anxiety. This raises the suspicion of false advertising – freedom from anxiety may be nice, but few would say it is positively pleasurable.
Still, in a world where even the possibility of missing out inspires fear, freedom from anxiety sounds pretty attractive. How can we get it? Mainly by satisfying the right desires and ignoring the rest. Epicurus thought that desires could be natural or unnatural, and necessary or unnecessary. Our natural and necessary desires are few: healthy food, shelter, clothes, company. As long as we live in a stable, supportive community, they are easy to achieve.
We become anxious when we devote energy to pursuing things that are unnatural, unnecessary or both.
More here.