We live in angry times. Physical violence used to scar match-days, leaving football specials trashed and a supporter with a dart in his nose, but those days are long gone because of CCTV, banning orders and conscientious souls forming campaigning fans' groups. Verbal violence has become the weapon of choice.
Caustic barbs are being thrown, not punches. Sociologists will signal a general shift in modern mores, to a culture where vocal confrontation is accepted and even promoted in sections of the varied, oft-frenzied television market.
The Olympics offered a brief glimpse of paradise, a land where everyone got on, but real life is not always so golden and amiable. Name-calling is almost a national sport. Even "pleb" has been heard again.
Platforms for expressing dissent are raised everywhere. Although well-established, radio phone-ins have become even more rant-filled - good for ratings if not for reasoned debate.
In social networking domains, tweets dripping with prejudice are propelled at John Obi Mikel, Carlton Cole and Sammy Ameobi. Racism writ large. If Michael Owen posts an innocuous tweet about the weather, a blizzard of abuse flies back his way from fans of clubs he left behind. Tribalism in 140 characters.
Many footballers join the microblogging service, hoping to engage with or inform their fan-base, and often retreat shocked at the tirade in return. Mikel, one of the sport's most likeable individuals, deleted his account last week. Too much invective. When Frank Lampard or Steven Gerrard, neither of whom are on Twitter, takes a corner in front of opposition fans, insults stream forth. "You just become used to it,'' shrugged Lampard.
But should he become inured to the venom of the chuntering classes?
Should any human being really be subjected to such vitriol? Anfield provides a focal point today (Sunday) with all eyes and ears on the fans, praying there will be no offensive chants about Hillsborough or Munich.
Down the decades, across assorted controversies, English football has arrived at more turning points than Karl Baedeker, but today feels a genuine watershed moment. Can football maintain the compelling match-day emotion while drawing out the poison?
Rivalry is healthy. The ideal atmosphere exists when there is an edge in the air but not an odious one. Mocking tragedies is "beyond the pale" to borrow the phrase of Sir Alex Ferguson. People died. Any chants about Hillsborough or Munich will damage the game markedly. Not just today's meeting of old foe but the game generally.
Football's critics, their slings loaded and arrows sharpened since the jolly Olympics, will unleash all manner of criticism, much of it justified, at the national game. If respect rules at Anfield, many of those considering drifting away, turning to less toxic sports, will have their faith in football restored. It is only a small step into the realm of hyperbole to claim that Liverpool and United are playing for the credibility of the game.
Football is the sport of extremes, a home to mindless chants and yet capable of wrapping the grief-stricken in its embrace, reminding them they are not alone, that their pain is shared. Anfield will see floral tributes, the release of 96 red balloons, and mosaics forming the words "The Truth", "Justice" and "96", a visual reminder of the fans' and families' long campaigns.
The concept of dignity is not an alien one in English football. While certain other sports carried on playing when news of Princess Diana's death filtered through in 1997, football immediately stopped, the first postponement coming at Anfield (where Liverpool were due to host Newcastle United).
Football is not the complete sport of shame as depicted by its growing army of detractors. Rugby union is a wonderful sport, setting for some of the most civilised crowds around, but some nutters can be found.
I'll never forget being at a rugby match in the Midlands when an Argentine's preparations for a penalty kick were interrupted by a gruff local voice shouting: "Remember the f****** Belgrano." Every sporting terrace has its idiots, but football undeniably has more than others (probably combined).
The majority of those attending today's game, a rite denied 96 Liverpool fans, will be models of decorum, showing respect, honouring those who died at Hillsborough and saluting their families who fought so long for justice. So the letter being handed to the 2,774 United fans as they enter the Anfield Road Stand, yards from the Hillsborough Memorial at the Shankly Gates, bears close inspection. It is from Ferguson and typically strikes to the heart of the matter.
"Our rivalry with Liverpool is based on a determination to come out on top - a wish to see us crowned the best against a team that held that honour for so long,'' writes Ferguson. "It cannot and should never be based on personal hatred. Just 10 days ago, we heard the terrible, damning truth about the deaths of 96 fans who went to watch their team try and reach the FA Cup final and never came back. What happened to them should wake the conscience of everyone connected with the game." Of all the words associated with the bard of Govan down the years, including the "football, bloody hell" response to the 1999 Champions League victory, to the observation that Ryan Giggs used to leave full-backs with "twisted blood", the Scot's plea to "awake the conscience" is powerful rhetoric.
Ferguson is right. It is time to awake the conscience, to appeal to supporters' better traits. Some of the terrace taunters lack a conscience, so it will require right-minded fans either to take them to task or sing louder, drowning them out.
Detecting who chants what in a large crowd is hardly an exact science, but CCTV is increasingly sophisticated. Those found guilty of offensive chants should be banned by clubs, just as earlier generations were expelled for acts of hooliganism. The authorities have been too lax for too long. Ask Sol Campbell. He had to endure some vile songs for years.
The battle can never be fully won. We live in angry times. It is difficult to locate a conscience in those who greeted United with a banner outside one ground (not Anfield) that spelt out MUNICH as "Manchester United Never Intended Coming Home". It's impossible to know where to start to bring enlightenment to such dark minds.
From board level to dugout and dressing-room, including some supporters' groups, Liverpool and United have strived hard to try to foster harmony today. One area that can still be improved - across many clubs - is the quality of stewarding and security in certain areas. If fans are treated disrespectfully, they may respond accordingly. The excessive cost of attending matches also shortens fuses when it comes to spleen-venting.
Following the sombre build-up, the players of Liverpool and United come to the fore, contesting the points with usual hunger but also mindful of maintaining a tone of respect, as the captains Gerrard and Nemanja Vidic have done. They must resist the usual sparring and snarling that accompanies this fixture. It is a day for Luis Suarez and Patrice Evra to forget last season's dispute and, borrowing the Premier League motto, to "Get on with the game".
The managers, Ferguson and Brendan Rodgers, will be urging their men to play the game, not the occasion, mixing ice with the fire in their veins. It is a day for experienced players. It is a day of questions, on the field as well as off. Who will take any penalties for United (if they get one)? Will Raheem Sterling make life uncomfortable for Rafael? Will Robin van Persie repeat the kind of movement that destroyed Liverpool's defence when Arsenal visited in March?
The game is weighed down with so much significance. Rodgers admitted that the gap between Liverpool and United hurt him.
"It does when you've been a club of this standing for so many years and the reality is that, on the field, you've fallen behind,'' said Rodgers.
"But it also brings great motivation that enhances my commitment to the cause, to show that we're going to fight to keep moving forward. Hopefully over these coming years we can close the gap.''
A show of closeness off the field today would be welcomed by all who love football. We need respite in angry times.