There have been many.
-The lack of enforcing obstruction and how it seems to change year to year because someone upstairs thinks it needs to be tinkered with every single year, depending on what point in the season we're in. Now here we are in yet another DPE.
-Instigator rules in the playoffs being turned over. What's the point of a rule if it can be broken at will. Enforce it!
-The Rogers monopoly. Greed at it's finest. A company that already makes billions by ripping off phone customers and their own TV service, yeah lets give them the games exclusively under the guise of growing the game. BS.
-The Sean Avery rule. First of all I don't agree with the rule. If a player wants to face the goaltender, thereby pretty much taking himself out of the play, that's his choice. But the NHL implemented a rule the very next day banning it. Yet when it comes to actual important things like player safety, there has to be committees, agreements with the league/PA and meetings held over a long length of time just to get new rules implemented. Yet when it's something that annoys the NHL, they can do it whenever they please.
-Lack of disciplining on various plays due to the fact it might be a star player in the playoffs. Mandating that ref shoudl be putting the whistles away come playoff time.
-Not doing anything with the oilers drafting 1st overall 4/6 years. Now the most marketable player since Crosby goes to literally the most undeserving team. Garbage.