In The Happiness Project, Gretchen Rubin wrote,
The feeling of control is an essential element of happiness—a better predictor of happiness than, say, income. Having a feeling of autonomy, of being able to choose what happens in your life or how you spend your time, is crucial. Identifying and following my resolutions had made me feel far more in control of my time, my body, my actions, my surroundings, and even my thoughts. Getting control of my life was definitely an aspect of my happiness project, and a greater feeling of control gave me a major boost in happiness.
quoted in David Murray, The Happy Christian