In Chapter 2 of The Great Gatsby we realize Tom Buchanan has a mistress. Before this chapter his mistress has been discussed, and Nick's heard about her, but it is in this chapter that he finally meets her. He tells the reader Tom insisted that he meet her, Myrtle, when they went into the city.
Though I was curious to see her, I had no desire to meet her — but I did. I went up to New York with Tom on the train one afternoon, and when we stopped by the ashheaps he jumped to his feet and, taking hold of my elbow, literally forced me from the car.
We also see Tom's arrogance when dealing with people who are below him in his eyes. When he meets with George to discuss selling him his car he is cold and condescending. When Wilson suggests that the man working to help Tom sell his car is slow, Tom quickly snaps back
“No, he doesn’t,” said Tom coldly. “And if you feel that way about it, maybe I’d better sell it somewhere else after all.”
Tom knows he has the upper hand in the deal and doesn't show the least it of remorse making a shrewd business deal with the husband of his mistress. We see that to Tom these are not people, but simply characters in his life to be manipulated for his own enjoyment.