In my opinion, the mood of Chekov's story is one of boredom with life caused by excess of wealth, too much leisure, and lack of purpose in existence.
The setting is a fashionable seaside resort in the Crimea, where the wealthy go to play. The progaonist, Gurov, is bored with his life; he has married to since he was a sophomore in college and has three children. It is the same of thing day after day, and Gurov has already relieved his boredom with infidelity long before they go on holiday.
When they arrived, Gurov discovers the other vacationers are not much different than those at home: timid, of marginal intelligence, and prone to routine. Although he engages in what he thinks will be an exciting affair, the woman proves tedious herself, concerned with her "morals" well after the act takes place.
Things do not get any better. Gurov observes those around him. He thinks:
"What savage manners, what people! What wasted evenings, what tedious, empty days! Frantic card-playing, gluttony, drunkeness, perpetual talk about the same thing. The greater part of one's time and energy went on business that was no use to anyone, and on discussing the same thing over and over again, and there was nothing to show for it all but a stunted, earth-bound existence and a round of trivialities, and there was nowhere to escape to, you might as well be in a madhouse or a convict settlement." (Part III).