I do exercise to keep thing ticking over. 5km jogs. You hear of people who experience feelings of well-being, even rushes of euphoria, to which they become addicted. Who *are* these people? Sport/exercise to me has always felt like being dragged around a field by a rabid bull. A necessary evil.
@Richard_Littler there are a select few people whose system just doesn't respond to exercise with an overflow of endorfins. We are in the minority, for most exercise can be pleasant and even very addictive. I've found kendo, which allows me to scream and hit people and while doing it get vigourous exercise. Running? yuck.