The problem is that his mentality should be the standard of any Man United player (every single player in the squad, including the ones who will not even make the first team), not something that stands out to be praised. You would never in 1000 years see a player celebrating an equalizer with 20 mins still to play under Sir Alex. People call this spoiled because we are not that team anymore, but the truth is that we can only be that good again if we demand this standard of every player on the pitch, every 90 minutes through the whole season, season after season. We are not that team anymore because we accept excuses instead of demanding this mentality of our players. If you're not first you're last.
We accept mediocrity now and it is the biggest reason we are not the best team in the country. There is some made up rule that because City were great 3 years ago and won the title by 1 million points, we need 10 years, a 31 year old manager from x/y league, and a CB who can pass like Iniesta in order to build a team that can win. Excuses is excuses. We would win the PL this season if every one of our players stayed the same in quality, but instead had Bruno's brain inside their head. Look at Real Madrid for example. People call their fans toxic etc, but any player or manager can go and they will remain where they are (long term) forever because if one day anyone senior at the club said that they want to get 3rd/4th with a smile on their face, there will be riots and people being killed in the streets. Us & Madrid are the only two clubs in the world of this stature, but we have forgotten what it means.
The fact that we even notice Bruno doing this shows everything wrong with our club. Even in Fergie's worst ever PL season (finishing in 3rd, when we finished 2nd very recently under Mourinho), if any player celebrated like that and it was not a winner (or a 96th minute equalizer), not one, but every single player on the pitch will reprimand that player. Rio/Keane/Waz/Neville whoever it is, they will bark at them to continue the game. You probably cannot find 1 single example of it ever happening in all of Ferguson's 26 years though, because it was not accepted. Everybody knew what was expected of them when wearing the Man United shirt. Listen to Evra talk about it and see the difference.
Bruno, Rashford & DDG are the only core players we have that are like this. Man United players. Matic & Cavani are also serial winners, with other clubs. Greenwood and Fred give 200% every game & have the quality, too. The rest of our players have a Spurs/Everton mentality, it is not their talent that is in question. They do not take responsibility on the pitch, and are not devastated whne we fail to win. Fletcher, Park, Rafael, O'Shea etc were great for this exact reason. When looking to sign a player to make up the squad, winning mentality will always be more important than what foot they prefer, passing % or some rubbish like that etc etc.
I have felt this for 5/6 years now, I cannot be the only one... I still think Solskjaer is the man. It is the players that are not the standard.