Sadly, postmodern American culture equates being an overachiever with being an obsessed workaholic with no social life. Children and people in general who are highly motivated and successful are scorned and looked down upon. They are viewed as obsessive and abnormal as compared to the rest of society.
There are some people who believe that it is good to achieve only a modicum amount of success and anything beyond that is unnecessary and excessive. They strongly insist that life is more than obsessively chasing towards and attaining so-called superficial goals. They maintain that life is more than achievement. They assert that people who are overachievers have something inner lacking in their lives and that is why the former are always achieving. Many people believe that overachievers are power hungry and control freaks which explains why they must always prove themselves.
Then, there are envious people who believe that no one should achieve beyond a prescribed level. These people strongly contend that since they are happy at their particular success/socioeconomic level, why would anyone else want to extend themselves. These people feel that what else do people want and what is the point of achieving a particular success level, aren't they satisfied with themselves the way that they are.
There are people who view overachievers as extremely single minded with extreme tunnel vision. They wonder what is the true impetus of the overachiever who is always striving and for what. They, in fact, feel sorry for the overachievers who never stop to appreciate the trees in which their main focus is the whole forest. They believe that the lives of overachievers is missing and sad; to them, overachievers are missing out on so many human components of their lives in some endless such of attaining some temporary superficiality which really means naught.