LONDON, England - Ask Ron Dennis what he misses most from the time when Ayrton Senna was driving for his McLaren Formula 1 team and the answer may come as a surprise.It is not the success, the domination or the three drivers' World championships and 35 races the Brazilian won over the six seasons they were together that the boss singles out. It is, quite simply, "the fun"."I remember the laughter and the fun," he reminisced to reporters at McLaren's Woking factory ahead of the 20th anniversary of the champion's death at the San Marino GP on May 1 1994.PRANK-LOVINGThe increasingly extreme practical jokes played out between the serious-minded Senna, prank-loving Austrian team mate Gerhard Berger - who replaced Alain Prost in 1990 - and Dennis have gone down in Formula One legend.There are the stories of Berger dropping Senna's supposedly indestructible carbon-fibre briefcase from a helicopter, of the Austrian filling the Brazilian's hotel room with frogs and replacing his passport photo with a picture of a penis.Senna retaliated in his own fashion, glueing Berger's credit cards together and putting a whiffy French cheese in the air conditioning of his hotel room.At Monza one year, Dennis returned to his plush hotel room at the five star Villa d'Este to discover it had been re-wallpapered with pornographic pictures.Dennis said: "Needless to say, when one of the group got back to his room later that night there was nothing in it. Nothing. No furniture. No clothes. Nothing."I remember the laughter and the fun. Normally there would be things verging on the slapstick and not so funny, especially damaging property which frequently happened... it was childlike but at the same time a really good feeling inside the team."DARK MOODSenna had been in a dark mood heading into 1990 after a controversial Japanese GP in which Prost won the title after the Brazilian was disqualified in what he considered as a conspiracy by the French-run International Automobile Federation.He had decided to retire but returned to find a very different team mate.Dennis said: "Gerhard gave me the perfect weapon to deal with Ayrton because he brought humour to the team. I would say the concept of telling a joke and Ayrton laughing at it was not even possible before Gerhard got in the team."But then that just created a massive ice-breaker."It got to the extreme. Gerhard has no limits. He'll go to the point where it is positively dangerous. There was one moment where we were up in Hamilton Island and were diving. And we were at quite a good depth and Gerhard just came and turned my air off. He thought that was hilarious."On another occasion, on Dennis's birthday in Australia, they threw the boss off a yacht and then chucked in bait to see if they could attract sharks.Senna was hard-headed about money, which he saw as both a measurement of his success and funding for his foundation in Brazil to help children in the favelas, and contract negotiations could be tortuous.To break a deadlock of $500 000 equivalent to R5.3million, he and Dennis once flipped a coin. It was only afterwards that they realised the contract was multi-year and that toss had decided a cool $1.5million equivalent to R15million.The money was to settle a wager that the Brazilian had lost in Mexico over whether the principal dared to down an entire container of fiery chilli sauce.Dennis said: "Before he could pull the bet back, I had wolfed it down. It was about the fourth time that he'd lost a bet, a big one, and I can remember him giving it (the money) to me and saying 'I am never going to bet with you ever again'."It's my fond memory for two things. To get a smile across Ayrton's face was not that easy. But to get him to part with his money with a smile on his face... it was a great moment. But I paid for it for a couple of days."RELIGIOUS INTENSITYSenna won the championship in 1990 and 1991 with Berger as his team mate but with Williams in the ascendancy, and champions for the next two years, he made his move. He died in only his third race with that team, aged 34.In the 20 years since, he has become a revered figure inside and outside the sport - held up as arguably the greatest driver of all time - and adored with almost religious intensity.His funeral brought more than a million people - and some estimates say three times that number - on to the streets of Sao Paulo and the acclaimed documentary 'Senna' retold the story for a new generation when released in 2010.The Brazilian had his failings, although those close to him say it was more absolute self-belief than arrogance, which were most evident in the notorious duels and collisions with Prost.He was a wily tactician, politically astute but also possessed of huge charisma, charm and deep spirituality. Dennis understood why his former driver and friend remained so adored."He was so good for all the period he was on the planet. I can see no positive-ness in the fact that he had an accident and lost his life. But you didn't see any decline," he said."I think there's lots of drivers that stay in the sport too long. And they tarnish their greatness. He was just unbelievably competitive and then boom! Not there."So what do you remember? I never thought 'I wonder what Ayrton would look like if he were here today?'. Well, one thing he would look is a hell of a lot older. And he would have had other things in his life that would have detracted from that reputation. He might have had a failed marriage."He just came to an abrupt end so you remember that greatness. That's one thing. And secondly he was great. Because he had human values, he was very principled."'CLOSE DOWN'Dennis was on the McLaren pit wall when Senna crashed in the San Marino GP, his third race for Williams. At that point, the man who had been one of those closest to the Brazilian took the decision to 'close down' emotionally."Some of the things in the 'Senna' film, the people that talk... I would say these guys know nothing," he declared.The Senna he knew, with his mastery of Monaco and brilliance in the wet, was "so awesome that it was hard to distinguish one bit of awesome from another. He was a great guy."