The concept of the playoff game makes sense, in a way.  You have a league that’s far too big for every team to play each other on equal footing over the course of a season, so you take the top teams from what we call a regular season and have them play a series of games that decide who the top team is overall.

Not all sports force this convention though.  Most notably, in soccer, the English Premiere League (EPL) treats the entire season as a tournament of the 20 best teams with each team playing every other team once