In order to understand, and appreciate, Athol Fugard's play MASTER HAROLD....and the Boys, one has to further analyze the historical context of the play, and the social context in which it is developed. This is what, ultimately, helps to explain the connection of these two elements to the relationships of the play.
Athol Fugard wrote MASTER HAROLD....and the Boys for two reasons. First, to expose the injustice of the Apartheid system. Second, Fugard uses his play to publicly confess how he, too, as a young man, was affected by this system. Fugard needed to sort of "ask for forgiveness" by exposing a horrible incident that he caused and led to severing ties with his black, best friend. However, we find that it is not so much Fugard who is to blame: it is the social manipulation that Apartheid brought with it which is primarily to blame.
Fugard's play takes place in the 1950's where Apartheid had just become a way of life. The term "Apartheid" was not coined until much later, but it was used to describe the way that the different racial groups in South Africa seemed to develop at extremely disparate levels. Nothing was officially questioned, until the entrance of Namibia (South West Africa) into the union.
Since Namibians had been disenfranchised, the UN ensured that the Indians from South West Africa receive political rights that will prevent mistreatment from the part of the (white) South Africans, once they become part of the union. This was a proposal made by India which openly exposed the racial inequalities of South Africa.
Hence, the National Party government of the Republic of South Africa (1948 to 1994) used a clever strategy to get votes: to instill fear in all South African whites by saying that all whites will be in danger unless they separate, racially and socially, the different ethnic groups. It is a "divide and conquer" technique.
Surprisingly, they did get the majority of the votes, and the practice became common in hidden tactics, in obvious acts of discrimination, by changing laws, and by manipulating all government agencies. Hence, Apartheid infiltrated every body of government, for example, the South African Police Service(SAP), which became notorious for its acts of terrorism and abuse against blacks, among many other agencies.
Back to the play, we can offer that Sam and Willie are the victims of Apartheid, which is based on: separating, exploiting, and repressing blacks. Sam and Willie are socially disenfranchised men. They are quite aware of this. They may have even learned to tolerate it. However, they are aware of what goes on outside of the tea room. Inside the tea room, the story changes, and they feel safe and loved there.
Hence, the relationship between Hally, Sam and Willie is almost unheard of in those days. The love that Hally develops for Sam makes up for his dysfunctional father, and the three are loyal and supportive to one another. Yet, when Hally (Fugard) insults and spits on Sam, is like re-opening the social wound that nobody dares to mention. It is twice as bad, and twice as hurtful. It is as if Hally had become one of "the others", and is the reason why Sam, simply, leaves and "stops caring:...The reaction of Willie says it all. It is an official break up, not only of the friendship between Hally and Sam, but also the end of the social trust that the three had developed together.