One theme central to "Stopping by Woods on a Snowy Evening" is the contrast between society and nature.
From the first stanza, the speaker is on a journey between two places. He decides to "stop" and simply "watch [some] woods fill up with snow." This presents nature as a place of respite—a space to find serenity and a quiet stillness.
The speaker considers how his decision to stop must seem "queer" to his horse, who is likely used to pressing forward from point A to point B as quickly as possible. Undoubtedly, the speaker initially departed on this particular journey with a sense of urgency since it is the "darkest evening of the year." Yet despite his plans, he finds himself stopping in the midst of nature, completely alone and isolated as he notes the "easy wind" which blows through this forest.
This place of respite stands in contrast to the man whose "house is in the village" and who likely owns this property on which the speaker pauses. The speaker wants to avoid being seen by this man, which further demonstrates his desire to avoid a return to the restrictions of society. After all, who determines ownership of a beautiful wood covered in a majestic snowfall? The owner will never know of this speaker's presence, which demonstrates an ultimate futility in society's need to lay claim to the natural world.
Although these woods are "lovely," the speaker must eventually tear himself from the serenity of nature in order to continue on his journey. His obligations pull him back into the society which he would rather avoid and away from the sense of calm stillness which nature provides.