the gold rush sets a classic example of how people would risk their lives and else to get money, or worldly possessions that is in association with money. some people steal because they are unable to provide for themselves or their families. some others steal because they want to keep up with the joneses but are unable to afford to do so without going hungry or getting evicted.
however, there are also the selected group of affluent people who steal simply for the "thrill" of the action. Where your heart starts racing and adrenaline pumps through your veins during the act and the smug satisfaction they feel when they get away with the act. For people like these, its akin to taking drugs or other substance abuse, it is simply to fill the void of emotion or time in their lives.