The NHL may not be mired in a PED scandal like the MLB, but that doesn't mean that there haven't been some awful moments that NHL fans have had to endure recently. Whether it was the 2004-05 lockout that cost the league an entire season or the atrocious Todd Bertuzzi-Steve Moore incident, there are certainly instants that the NHL would like to forget.
Of course, the various reasons that the league would like to forget these moments varies greatly, based both on severity and circumstance.
With that in mind, by "moments the NHL would like to forget," we mean "moments the NHL wishes had never happened."
Some of these snapshots in time cause pain because of financial reasons, and others because lives were drastically altered on these particular days. These types of events obviously aren't equal in importance, but the NHL—and probably most fans—would do anything to prevent these occurrences from going down in the first place if presented with the chance.