I think that evolution has had a hand in selecting people who had a sense of doing something beyond themselves.
Mihaly CsikszentmihalyiThose periods of struggling to overcome challenges are what people find to be the most enjoyable times.
Mihaly Csikszentmihalyi..Such practices and beliefs, which interfere with happiness, are neither inevitable nor necessary; they evolved by chance, as a result of random responses to accidental conditions. But once they become part of the norms and habits of a culture, people assume that this is how things must be; they come to believe they have no other options.
Mihaly CsikszentmihalyiEnjoyment, on the other hand, is not always pleasant, and it can be very stressful at times. A mountain climber, for example, may be close to freezing, utterly exhausted, and in danger of falling into a bottomless crevasse, yet he wouldn't want to be anywhere else. Sipping a piรฑa colada under a palm tree at the edge of the turquoise ocean is idyllic, but it just doesn't compare to the exhilaration he feels on the windswept ridge.
Mihaly Csikszentmihalyi