The Happiness Advice Industry points to contentment as an internal, personal quest, separate from other people. America The Anxious, by Ruth Whippman notes this in her book. Some amount of solitude is important for a healthy life, for prayer, reading, yet Whippman points out that all the research agrees that happiness depends on interaction with other people. I see this even in the monastery. The happiest, most content monks seem to be the ones that have sufficient time with other monks. They are not hermits. Interaction in your own life can come from family, co-workers, being part of a group that tries to help others and even chatting with someone while waiting on line in a groceery store. I have found that being of service for others promotes my own happiness. And I am an introvert.