John Steinbeck's Of Mice and Men was first published in 1937. In the book, he tells the story of two men, George and Lennie, who are wandering laborers in California.
In this work, Steinbeck presents conflict in a very personal, very realistic way and as between a small number of people, usually only two people, one of whom is of a higher intellectual or social class than the other. Often, the other party does not fully comprehend that conflict is arising, especially in the case of Lennie, who causes conflict and is the recipient of hostile actions and attitudes.
Sometimes the conflict is between friends, such as George and Lennie. Lennie, however, is confident, though, that George will always be there for him, even if George becomes angry with him.
We also see sexual conflict in the story, as Curley's wife has "got the eye" for other men after only two weeks of marriage. Accordingly, Curley is a jealous man, which is what contributed to his attack on Lennie.
At other times, the conflict is physical and involves one party who has no idea what has caused the conflict, as when Curley attacks Lennie. This sort of conflict makes it appear that Steinbeck had a few boxing matches in his time: "He slashed at Lennie with his left, and then smashed down his nose with a right."
The most prominent type of conflict in the story, as mentioned above, is unwitting conflict. Lennie's mind is so simple that sometimes he does not realize that his actions cross the line between curiosity and harm. Thus, his attempt to touch the woman's red dress resulted in an accusation of attempted rape and caused George and Lennie to have to flee from Weed, California. This event foreshadows Lennie's unwitting killing of Curley's wife, who invites him to touch her hair.
Interestingly, we should also note the naturalist similes Steinbeck uses when describing Lennie's crushing of Curley's hand and his killing of his wife. In both instances, they are described as flopping "like a fish."