In Dreams from My Father, what difficulties does Obama describe having as a child?

In Dreams from My Father, Barack Obama describes the difficulties of not fitting in with others and being a social outcast as a child because of his racial identity.

The difficulties that Obama experienced as a child because of race are documented in different portions of his narrative.  One such moment is when he was a ten year-old new student.  The homeroom teacher, Mrs. Hefty, spoke glowingly about "Barry's" Kenyan heritage in front of the other students. Obama communicates the difficulties of being different from others when she asks him about his tribal affiliation:

Her question brought on more giggles, and I remained speechless for a moment. When I finally said 'Luo,' a sandy-haired boy behind me repeated the word in a loud hoot, like the sound of a monkey. The children could no longer contain themselves, and it took a stern reprimand from Miss Hefty before the class would settle down and we could mercifully move on to the next person on the list. 

Obama's difficulties in fitting in with the other children are due to his racial identity.  When the other children "could no longer contain themselves" from laughing at him being African, he felt like a social outcast.  He describes how he was "in a daze" for the rest of that day. Children asked to feel his hair, as if he were a pet, while another child asked if his father "ate people."  When Obama goes home after that first day, he cannot answer his grandfather as to how his day went.  He simply closes the door to his room, knowing that he does not fit in with white children.  The personal and emotional details that Obama employs to describe this experience communicate his difficulties in being "different" than the cultural majority.