The emotional investment may have made him miss out on more interesting, better compensated, or otherwise more desirable jobs. And the pain at its end does not correspond to more enjoyment. I don't think a mercenary attitude diminishes the enjoyment of working at all. Like I said earlier, the Blackwater and Executive Outcomes guys probably enjoy their jobs just as much as typical soldiers - possibly even more. I don't this this is a trade off between more enjoyment and greater emotional damage at the end. It's just as much enjoyment, better impact on his life situation, and less pain when his job ends. A strictly better set of outcomes.