as compared to other, more physical, hustle driven sports.  in football, if you HATE losing, you can dig deep and overpower your opponents late in games.  in basketball, you can sustain your defensive intensity for all 48 minutes.  in hockey, you can absolutely refuse to give up on a scramble for a puck along the boards and give your team a better chance at digging it out and turning it into something.  (ok, im not that much of a hockey fan so i had to think for a while to come up with that, but the point remains that hockey is more physical than baseball.)  but in baseball, there are basically no chances to outmuscle or overpower an opponent.  all you can really do is focus harder.  and even when you do, if youre a batter, what if you hit a scorcher straight at an outfielder and he catches it?  if youre a pitcher, what if you put a perfect pitch right where you want it and the batter hits it out of the park anyways?  when youre in the field, what if the ball never gets hit to you in a key situation?  except for a truly out of this world, johan santana type pitcher, baseball really is more dependant on luck than any other sport.  as a batter the difference between a 0-4 day and a 3-4 day might be a total of 30 feet of distance (either left/right or deep/shallow) on those 3 hits or outs.  unlike a point guard or a quarterback, even great baseball players (except for the santanas/carpenters/halladays on a good day, as i already said) have trouble taking over a game on a good day.  its just not that easy.  so i cant really answer your question about what it takes to teach not losing, but i will say its much harder in baseball than in other sports.  all the david ecksteins in the world cant magically come up with the key hit or play at the rate a jordan or a john elway did.