From the first time the reader meets the character of Tom Buchanan, Fitzgerald's language begins to paint a picture of an unpleasant individual. Nick observes Tom to have changed since they were college classmates, now observing Tom to have "a rather hard mouth and a supercilious manner. Two shining arrogant eyes...a body capable of enormous leverage- a cruel body."
Nick's first conversation with Tom adds to the reader's impression of Tom, not in a positive manner. Tom presents himself as being conceited and condescending in his mannerisms.
Now, don't think my opinion on these matters is final," he seemed to say, "just because I'm stronger and more of a man than you are.
Tom's first actually spoken words are intended to insure that Nick is impressed with the Buchanan mansion, not to find express any interest in Nick's activities since they last met. "I've got a nice place here...It belonged to Demaine, the oil man."
Tom's actions, as the story progresses, continue to reinforce his unappealing character. Tom married Daisy in June and they left for their three month honeymoon. Since their daughter was born the next April, Daisy must have become pregnant sometime in the first half of that three month period, meaning they probably were aware of the pregnancy when they returned to the United States at the end of the three months, sometime in August. Despite that knowledge, Tom's name appeared in the Santa Barbara papers shortly after their return due to his involvement in an auto accident and the injury of his passenger, who was "one of the chambermaids in the Santa Barbara Hotel." Not a very pleasant episode for a newly married and expecting husband to be involved in.