why is Booker not bitter and anguish despite being a slave ?

In Booker's own words,“I will not let any man belittle my soul by making me bitter.”

Washington was a devout, learned Christian. He did not allow the things he struggled with to shadow his life; he worked to abolish the shadows.

"It is now long ago that I . . . resolved that I would permit no man, no matter what his colour might be, to narrow and degrade my soul by making me hate him. With God’s help, I believe that I have completely rid myself of any ill feeling toward the Southern white man for any wrong that he may have inflicted upon my race. . . . I pity from the bottom of my heart any individual who is so unfortunate as to get into the habit of holding race prejudice."