In my view, what greenmachine posted is true, if you are a fan of MLB and Barry Bonds type.
Only a player like Bonds can produce with that level of skill and confidence.
Take Bonds out of a lineup, and you end with an under-performing Giants lineup that gets their hitting coach, Carney Lansford, fired.
My view is we have to appreciate whether this question does relate to the level of play and whether it is HS, college or Milb or MLB. For the most part, it is easier to relate to HS and college although Joe Torre's book, The Yankee Years, shows it applies in MLB, also.
For HS and college, the issue is largely leadership.
For college, there are certain players who are there day one to greet the freshman, who acquaint them with what it means to be a champion, who are the first ones in the weight room at 6am to meet them and the last to leave. They are the first ones at practice and the last to leave.
Finally, they are the ones who breed a level of confidence, of humility, of challenge and acceptance. To "win" in college, freshman need either a huge amount of "Bonds" type talent or they need leaders who show them how to play the game and how to succeed and how they will succeed.
I will never forget a pitcher at Stanford in 2008 who took the ball every week, went 9 innings, competed with passion, I mean passion, and literally willed his team to Omaha. I am not sure he was an over achiever as opposed to making many on his team/in his line up over achievers. He sure made everyone better and made a team of winners.
In HS and college, good coaches coach each and every player to know his job, to know he has a job to do and to know he has the skills to "win" a battle when the opportunity arises.
The confidence they will "win" that battle begins in August and September in the weight room. It continues when that player, is in the classroom and does what they need to do to succeed for himself and to be on that field, and it continues when they arrive at practice until they leave.
It is easy for Bonds to be an over achiever.
He is the exception.
Most over achievers do it by leadership, by outworking everyone else, by creating a winning environment from the first day of classes, and by doing each and every job they are given by each and every sign the coach gives during the season.
Over achievers identify what needs to be done, in part because they know and in part because the coaches identify it for them.
Most importantly, they win each battle, whether it is getting a bunt down when required, hitting behind a runner to advance runners into scoring position, or having an AB that gives every other hitter confidence. Over achievers work an AB and elevate a pitch to the outfield to score a run when it is 1-2, 0-2 with a runner on 3rd. Over achievers do this so others see you don't need to be Bonds to succeed, you need to know your job, and do your job.
As I post many times, you don't have to be a great player to be in MLB, you have to be a good one everyday.
When you do your job everyday as a player or coach, and others know you do, you truly are an over achiever that can make a difference, whether you are playing, or coaching those who are playing.
The game of baseball is not an easy one to know your job and to win that battle.
Over achievers know their job and win the battles more than .333 and they create a level of confidence where the .250 guy knows he can be the .300 guy, and he does.
Good selfish players better be Bonds type players.
For everyone else, selfish players succeed as individuals but their teams often time suffer and underperform.