Both Lee and Grant served under Winfield Scott who used an early form of overwhelming force in the Mexican War. Lee tried to use a similar tactic in the two northern invasions and failed, partly due to inadequate supply lines. Grant was able to use overwhelming force because he had the resources and he knew the south didn't. I've always felt that the generous terms Grant gave Lee at Appomattox was a gesture of respect, Grant knew that it wouldn't have been a fair battle and he also knew that in a "fair" fight the "safe money" would have been on Lee.
Becuase I'm from Maine and I can't resist...
Joshua Chamberlain.
And I know I'll get crap for this one, but what the hell...
Benedict Arnold (before he became a traitor)
And a man who deserves the MOH...Richard Winters.
Grant was following President Lincoln's desire to reunite the country following the war, and he respected Lee, but he didn't give Lee favorable terms because it hadn't been a "fair fight."