I don't believe the best team wins the Cup. Didn't think the Penguins were the best team this year, and don't think the Capitals or Knights are the best this year.
Winning a Stanley Cup takes an astronomical amount of luck. It is far more luck oriented than the NBA, MLB and NFL. Players shoot the puck, hoping it goes in off someone's ass, and that can be the game winning goal of the series.
While I don't think NHL officiating is the worst amongst the four major sports, it's up there and they're incompetent to a large degree. Their calls/missed calls further amplify the magnitude of luck in the sport.
All the playoffs show is [a] which team got hot in May, which team was consistent, and [c] what team had the most luck.