LONDON, England - If Formula 1 were to produce a good-feud guide then the rivalry being cooked up between title-chasing Mercedes team mates Lewis Hamilton and Nico Rosberg would merit several stars.While their bosses will do what they can to keep the drivers in check they will also let them race - which means the increasingly fractious duo will have plenty of fuel in the coming months."We are not friends, we are colleagues," Hamilton declared in Monaco on Sunday (May 25) after Rosberg won the season's glamour race and seized back the championship lead with a four-point advantage.FRIENDS OR FOE?Hamilton, the 2008 Drivers' champion, hardly needed to spell that out - body language did it for him in a podium "celebration" that ended without handshakes or back slaps between the Mercedes drivers who finished first and second."We are living in the same building and I am sure when we turn up in the next place we will be as professional as ever," a calmer Hamilton explained later. "People say we are best friends but we are not. We have not been since we were 13. I say 'hi!' to him and he says 'hi!' to me. We don't have lunch together; we don't have dinners. We are cool."Rosberg, visiting the German soccer team on Tuesday (May 28) told reporters he was sure relations would improve - even if Hamilton would be hoping the next dish served up in Canada would be cold and labelled "revenge"."We've always been friends, we always will be friends," Rosberg had told Sky TV after the Monaco race, "but friends is a big word. What exactly is friends? We have a good relationship and work well together".ADDED SPICEMuch of the spice in the unfolding story is that until the 2014 season in which Mercedes is so dominant that it could end up winning every race the drivers were were as close as any F1 pairing despite being very different characters.Hamilton and Rosberg, one growing up in a post-war suburb in England and the other as the son of an F1 driver and millionaire in Monaco, have known each other since they were teenage team mates in karts. They travelled together and had a glimpse of the good life enjoyed by Rosberg's 1982 Drivers' champion father Keke.Until recently Hamilton even kept a safe in Rosberg's apartment.That they should now fall out is par for the course in F1.David Coulthard, who sometimes faced stony silence from double champion Mika Hakkinen during their time together at McLaren, wrote in a London Daily Telegraph column on Tuesday (May 27): "You can talk as much as you want about them growing up as friends but you have to out-perform one man."No matter how long you have known them you only find out who they are and what they are really like when the light is shining brightest."As four-times Drivers' champion Alain Prost warned earlier in May 2014, few friendships survive in F1 when such a prize is at stake and those fighting for it are in the same team. He should know, having partnered late Brazilian triple champion Ayrton Senna at McLaren in one of the most combustible pairings of all time - and one whose echoes are being detected again.BAD LOSER"Show me a good loser and I'll show you a loser," Hamilton's former boss and mentor Ron Dennis likes to say, and he is certainly not alone in thinking that.Point out a happy, friendly pair of team mates on the grid and it is usually because the pecking order is clearly established - think Michael Schumacher and Felipe Massa during their time at Ferrari - or the car is not good enough to allow either to do much more than take part.It is no coincidence that Hamilton got on well with Heikki Kovalainen, who posed no threat as a McLaren team mate, but was barely on speaking terms with double Drivers' champion Fernando Alonso during their year together in 2007. Alonso felt Hamilton was favoured by Dennis and seethed. In Monaco, it was Hamilton who felt Rosberg had deliberately stymied him and was similarly aggrieved."I wish you could have seen the data," Hamilton told reporters on Sunday, referring to the Monaco controversy that saw Rosberg take pole after messing up his final qualifying lap and bringing out warning flags that denied him a chance to go faster."I saw something late on last night, and all I could do was smile." It might be some time before that smile is directed at Rosberg, however.But Niki Lauda, a triple champion who is now non-executive chairman of the Mercedes team and was instrumental in luring Hamilton from McLaren, said he would ask the two to show at least a degree of courtesy in public, no matter what was bubbling away in the background."I had the same with Prost. I hated the guy," Austiran Lauda said of the McLaren team mate he beat to the 1984 title by a half-point, "but at least I said hello in the morning."