Respect. The world could do with a lot more of the stuff - between countries and cultures, between races, between men, women and children, and between cricketers.
Respect is what keeps confrontational sports like cricket civilised. Most of the time. When it is lost in a moment of madness, the void is quickly seen, heard and felt.
Like it has been too often on Australia's tour of South Africa, what with five players falling foul of the code of conduct in just about eight days of play.
As much as it's up to captains, match officials and the International Cricket Council (ICC) to maintain the balance between passion and petulance, the first arbiter in this tussle should also be the last: the individual.
"You want to play the game hard but there's got to be respect," Graeme Smith said. "A lot's been made of this 'line', but to make anything personal is not on. I've always really been against that.
"But it is competitive sport and there are high emotions and heated moments, so things are going to happen."You also don't want to take that out of the game. It needs to be managed and it must be kept respectful, but people want to see that - the passion and the want to win and the big competition.
"When 'KG' [Kagiso Rabada] was bowling at [David] Warner [in the second innings at St George's Park], that was magnificent to watch and you don't want to lose that fire in a series. It's a fine line to manage.
"I get really frustrated with the inconsistencies of the management of these things. I think too much is being managed from [ICC headquarters in] Dubai, and that needs to be reassessed.
"To appeal [against a verdict] generally means you get a harsher punishment, so in some ways they're not allowing people to state their case.
"I think there are people sitting in Dubai who are a long way from the context of the situation, and they maybe need to put more trust in the people they appoint to do their jobs."
So does cricket have a disciplinary problem, or does discipline have a problem with cricket?
Or is the way the ICC wants to enforce its demerit system confusing players and inflaming tensions between teams?
"The players know all about the code of conduct because it has been in place for more than 10 years and this is the framework in which they ply their trade," an ICC spokesman said.
"Many countries have an almost identical list of offences in their code of conduct for domestic competitions."Professional players generally operate under the framework of the same behavioural offences in whichever competition they play.
"When the demerit points system was introduced [in September 2016] there was no change to the offences in the code of conduct and no change to the sanctions for each individual offence, so what players can and can't do on the field remains as it has done for a number of years.
"The demerit points just formalised the way in which a breach was recorded against a player, and laid out the consequences if the player repeatedly breached the code."
That brings us to Rabada, who will put his case for an appeal against his two-test ban to ICC judicial commissioner Michael Heron tomorrow.
Rabada's ban was enforced when he reached eight demerit points after being punished for the fifth time in 13 months.
If Rabada's appeal is successful, he will play in the third test at Newlands on Thursday. If he isn't, he won't.
"There are plenty of players who play the game with passion who don't come close to breaching the code," the ICC spokesman said.
"Passion is part of the game, indiscipline and disrespecting your opponents is not."..