Possibilities.
Possibilities are indeed interesting things, as these possibilities are what form the multiverses, so much so that it may as well be confused as time travel, but then… that is a matter for a different story.
The story of 'oregairu' which is known of, is much to the unfortunate life of Hikigaya Hachiman, however, in the show a line that caught attention was that of "if only I met you ten years ago." or something like that.
Now, one may have been thinking about that this story has one Ms. Hiritsuka "eternal bachelorette" Shizuka, but no, it isn't.
After watching the entire show, there was a feeling like there were various ways things could have been… different, a better different if certain events, or rather – chance meetings happened before hand. How things would of change and what would come of it.
This is a story of these chance meetings happening and what they resulted in thereof.
Possibilities.