Steinbeck introduces drama into every chapter by creating small conflicts between the various characters. It can be seen that every chapter of the novella contains at least one conflict, and conflict is the basis of drama.
In chapter one, George and Lennie are just preparing to camp overnight before reporting for work. First there is a conflict over Lennie's dead mouse. George has to threaten to sock him before Lennie gives it up under protest. There is a minor conflict over the beans. Lennie mentions that he likes catsup with his beans, and this stirs the smoldering anger in George, who berates his companion for all the trouble he causes him. And this brings up the incident in Weed, which forced them to leave the town and head for the Salinas Valley. The Weed incident will be described at greater length when George confides in Slim, and it will be seen that it was a very dramatic event which almost cost both men their lives.
In chapter two, George quarrels with Candy over the yellow can of bug powder. Then the Boss shows up and vents his anger on George for not showing up on time. It appears that George and Lennie don't even have their jobs yet. There is a lot of explaining and verbal abuse before they are finally signed up. Before the chapter is over, George has a confrontation with the pugnacious Curley, which foreshadows serious trouble. Curley's coquettish young wife foreshadows more trouble when she makes an appearance in the bunkhouse doorway.
In the next chapter there is a conflict over Candy's old dog, and then there is the fight between Curley and Lennie.
In chapter four, several people intrude into Crooks's room, and there is conflict between Crooks and Lennie and then between Crooks and Curley's wife, who shows her mean side when she frightens Crooks by suggesting that she could get him lynched if she wanted to.
Then in chapter five there is an intensely dramatic situation which ends with Lennie accidentally killing Curley's wife.
The last chapter, back at the campsite by the river, includes a lynch mob looking for Lennie. George kills Lennie to save him from a torturous death at the hands of the lynch mob. George experiences a serious internal conflict because he doesn't really want to kill his friend but feels compelled to do so.
There are many other minor conflicts throughout Of Mice and Men, including those between Curley and his wife and between Curley and Slim. The conflicts create the impression that life is an ongoing struggle for survival and that conflicts are unavoidable. Readers who have never had to do hard labor or live in subpar bunkhouses will still identify with these men because the readers' own lives--unless they are exceptionally lucky--are rarely free of petty conflicts and occasionally serious and ominous ones.