By the time the games are played, the players pretty much know what's coming, and, because the playoffs are so much of a half-court game, scoring can be particularly difficult. They become more controlling over their offenses, and while we've all done it, it's a bit of a mistake, because it can cut down on easy baskets.
Most easy baskets come from a transition game, but that also can lead to turnovers.
So coaches take away some instinctive reactions from their players, and it's up to the stars to make the plays. There's a tremendous emphasis on your point guard, who's the key player on the team in the regular season, and even more so in the playoffs. Previous failure or success against your postseason opponent is a definite factor, because the style of a certain team will play well against other styles, and there are advantageous matchups. People say it's a new season, which is true, but the players know the records. When one team dominates the other during the regular season, it's crucial that the team that's been dominated have a good first game.