Neil Warnock is certainly learning the hard way how tribal this rivalry is between Cardiff City and Swansea City.
He has been involved in big derbies before, of course, namely the Steel City derby while in charge of Sheffield United and other high-profile clashes in London, but he acknowledges this might be a little different.
So much so, in fact, the Bluebirds boss has been accosted in his local supermarket and even has to avoid his favourite restaurant until the fallout from derby day has blown over.
"The fans have been telling me how much it means to them as I walk around the supermarket," Warnock said.
"In one of my favourite restaurants in Bridgend, Franco's, Franco is a mad Swansea City fan. I daren’t go to his restaurant this week because I’m not sure what he’ll feed me.
"We had a laugh about that.
"You don’t get games like this all over the country – they are special."
Warnock conceded Swansea, and Steve Cooper, have made an impressive this season.
He knows his players will have to be on it from the very first kick of the ball today, but predicts a frantic start to proceedings at the Liberty Stadium as the adrenaline pumps around the players' bodies.
"We have to start well," he added, "but that is never a problem in derby matches.
"I don’t think the ball will touch the floor in the first 10 minutes. Even with Swansea.
"It is like Wacky Races because of the atmosphere in a derby match."
