John Steinbeck understood that fiction must be dramatic and that drama is based on conflict. There is not one great conflict in Of Mice and Men, but it should be noted that the author intentionally invents little conflicts for every chapter in order to sustain dramatic interest.
In the opening chapter, for example, there are only two characters, George and Lennie. So Steinbeck invents conflicts between them. One conflict is over the dead mouse. Lennie doesn't want to give it up. George threatens to sock him. There is a small conflict over the fact that George wants to sleep by the river and Lennie would like to go on to the ranch so that they could get a meal and have bunks to sleep in. They even have a conflict because Lennie says he likes catsup with beans.
"There's enough beans for four men," George said.
Lennie watched him from over the fire. He said patiently, "I like 'em with ketchup."
"Well, we ain't got any," George exploded. "Whatever we ain't got, that what you want."
George recalls the big conflict in Weed caused by Lennie molesting a girl on the street. They had to run for their lives. And George berates Lennie for always causing him trouble. Lennie responds by saying he will leave and live by himself in a cave if George doesn't want him. George foreshadows more conflict in the future because he says that Lennie is always causing him trouble.
So in the next chapter Steinbeck needed more conflict. He invented an argument between George and the boss. The boss seems unnecessarily suspicious and hostile. There was a danger that George and Lennie might not get the jobs they were counting on. If so, they would be flat broke and back on the road. They ate their last three cans of beans the night before. When this conflict is resolved, Steinbeck invents another conflict over the can of bug powder George discovers in the box above his assigned bunk. This is just conflict for the sake of conflict--drama to enliven what could be a pretty dull story about working stiffs on a ranch.
There are many more conflicts throughout the short novel. For example, Carlson wants to shoot Candy's dog and Candy doesn't want to lose his pet. Curley provides lots of conflicts. He has conflicts with his young wife, with Slim, and finally with Lennie. Crooks has a conflict with Lennie and another conflict with Curley's wife, one which she wins by hinting that she could get Crooks lynched by telling the men he molested her. There is an important conflict between Lennie and Curley's wife in the barn, ending with the girl dead of a broken neck. When Curley's wife tells Lennie about her recent life she makes it clear that the girl was having serious conflicts with her mother.
"I lived right in Salinas," she said. "Come there when I was a kid. Well, a show come through, an' I met one of the actors." He says I could go with that show. But my ol' lady wouldn't let me. She says because I was on'y fifteen."
George and Lennie are in a boring setting doing arduous and monotonous work; nevertheless, there are all kinds of conflicts created by the author to give the "naturalistic" story an aura of drama.
The boss is suspicious of George, wondering if he has "a stake" in Lennie; that is, if George takes a part of Lennie's earnings because he always talks for both of them.
After George and Lennie arrive at the ranch, the old swamper named Candy shows them to the bunkhouse. Having lost his hand in a machine, he is now relegated to cleaning the bunkhouse, so George questions him about the previous occupants of the beds. This suspicion of George's arises from not knowing anyone and distrusting other people's motives as Candy has denied that there were any "graybacks." This reaction of distrust on George's part foreshadows that of the boss's distrust, who enters shortly thereafter.
The boss is suspicious of George and Lennie from the beginning because they have arrived later than they were instructed.
"Says right here on the slip that you was to be her for work this morning,"
the boss tells them. George then informs the boss that the bus driver made them walk ten miles the previous day, and they were unable to find a ride in the morning. When the boss asks further questions, George answers for both of them. Suddenly, the boss questions Lennie in order to force him to respond; however, Lennie looks to George in his panic since he has been told to keep quiet. Again, George replies for Lennie, angering the boss.
The boss turned on George. "Then why don't you let him answer? What you trying to put over? ... Say--what you sellin'?"....what stake you got in this guy? You takin' his pay away from him?"
"No, 'course I ain't [George replies]. Why ya think I'm sell'in him out?"
"Well, I never seen one guy take so much trouble for another guy. I just like to know what your interest is."
George fabricates an excuse that Lennie is his cousin, and he has promised Lennie's mother that he would care for him after Lennie was kicked in the head by a horse. But, Lennie can do any physical task asked of him, George adds.
This line of reasoning seems to satisfy the suspicious boss; still, he warns George,
"...don't try to put nothing over 'cause you can't get away with nothing. I seen wise guys before...."
This dialogue indicates the distrust and alienation of men during the Great Depression. Uprooted from their families and friends, most of the men were on their own, and were, consequently, under suspicion by strange employers as well as very suspicious of other men.