For some people completing rings or seeing numbers go up is satisfying. For the same reason completing all quests in an open world game or leveling up a charac

For some people completing rings or seeing numbers go up is satisfying. For the same reason completing all quests in an open world game or leveling up a character in an MMO is satisfying and addictive to some people. This is useful for those who don't find working out in itself to be a rewarding activity and may have a hard time sticking with it otherwise.