I heard Raja Bell refer to their upcoming game against the Lakers as it being a playoff game for them. And I heard Gilbert Arenas refer to their game against Cleveland this year as their playoff game. It happens a few times a year, when a team with a losing record plays a rival or big-time team that they match up well against and they play as hard as they can. They really believe they can win.
And they usually do. And if not, they at least cover the spread. In the NBA especially, certain teams just match up well against superior teams. Not every team, obviously, but against that one special team they match up well. Like the Warriors and Mavericks in the 2007 playoffs.
But this is usually a rare occurance and I don't think it is ever reflected in the spread for games. Nevertheless, this is a major factor in the outcome of the game. It is a gametype I need to look out for. Its not necessarily a cognitive bias but it is definitely a game type.
I call it "the playoff".
The Cavs were 12 point road favorites to the Wizards. The Wizards arena was sold-out. Considering they have less than twenty wins this season, that is indicative of how much it was rocking. Also, when the Lakers visited Charlotte this year, the stadium had its largest crowd....ever.