Have you ever sat down to eat something for the first time and thought, "Well, this is overrated"? On the flip side, maybe you've found yourself saying, "Wow, this is surprisingly good!"
This type of thing applies to many areas of life. Things are overrated and underrated. Snacks, movies and music -- you name it, we rate it one way or the other.
The same goes for sports players and teams. Teams overperform and underperform relative to expectations, but odds say they are bound to regress to the mean one way or the other, especially baseball teams who have a 162-game sample of a season.