In "Winter Dreams," during the winter, how does Dexter reflect upon his summer activities?

In “Winter Dreams” by F. Scott Fitzgerald, Dexter spends the winters of his youth musing over the lives of the wealthy members of the country club where he is a mere caddie. He sees himself playing matches with and against the club members, winning the club championship, and driving an expensive car. He longs not only to be like these men, he longs for the things they have. In his dreams, he is a man of prestige and accomplishment.

But do not get the impression, because his winter dreams happened to be concerned at first with musings on the rich, that there was anything merely snobbish in the boy. He wanted not association with glittering things and glittering people—he wanted the glittering things themselves.

Judy Jones enters his life when he is only fourteen years old, but she steers the course of his life into his thirties. His winter dreams focus on his obsession with this beautiful but fickle young lady. When he is with her, his dreams are fulfilled.

She simply made men conscious to the highest degree of her physical loveliness. Dexter had no desire to change her. Her deficiencies were knit up with a passionate energy that transcended and justified them.

Unfortunately for him, Judy moves from one man to the next without a thought for their feelings. As the seasons change, he begins to realize that he cannot have her and he tries to move on, even becoming engaged to another. “When autumn had come and gone again it occurred to him that he could not have Judy Jones.” But again, Judy appears and his stability is torn away once more. In spite of his success as a businessman who fulfilled his original winter dreams, Dexter is unable to let the dream of Judy die.

War intervenes, and upon his return, he builds his business in New York. During a business meeting, he learns of Judy's marriage. According to an acquaintance, she is in a difficult marriage, and her looks have dwindled. Only after hearing this does Dexter realize that although he attained his youthful “winter dreams,” he sold his soul for Judy Jones.

Even the grief he could have borne was left behind in the country of illusion, of youth, of the richness of life, where his winter dreams had flourished.

"Long ago," he said, "long ago, there was something in me, but now that thing is gone. Now that thing is gone, that thing is gone. I cannot cry. I cannot care. That thing will come back no more."