Compare jab speed, study punching power, analyse knockdowns. Then tell me: Muhammad Ali or Joe Louis? Bury me in stats and lay it on the line: Jordan or LeBron? Federer or Rod Laver? Rate them, weigh them, praise them and decide: Pele or Maradona? Tiger or Nicklaus? We can do this all day and come to no conclusion except that too many beers dilute an argument.
Who is the greatest? No one knows and yet everyone comes armed with an opinion, a fact sheet and a bias. A website which has possibly never heard of Larisa Latynina wrote that Simone Biles is the greatest gymnast of all time. Biles hasn't yet won an Olympic gold; Latynina has nine. Absurd, we say, yet we're much the same. A watcher will promise he's as impartial as a marriage counsellor and yet will pick Steffi Graf over Serena Williams only because she snarls less.
No fisticuffs break out when we discuss Keats and Byron, no sulking occurs as we debate Bach and Beethoven. But in sport we can't help ourselves for we're naturally inclined to rank, rate and slot athletes as if talent can be neatly laid out in an accountant's ledger. We don't care for boasters but must show off our knowledge to each other.
We'll scrutinise strengths, mine history and invent mythical matches. Last week Richard Krajicek said that if Federer plays Pete Sampras 10 times at Wimbledon he wins 6-4. Feel free to howl in protest. ESPN ranked the top 20 tennis players of all time and Federer was first, Steffi Graf second, Serena third, Martina Navratilova fourth. Margaret Court, whose 24 Grand Slam titles Serena is chasing, was 15th. Foam at the mouth if you wish.
Don't you hate these greatest-ever debates? Don't you just love them? We pretend it's all serious when really it's beautifully childish. We quiz experts and innocently expect these humans to be objective. Years ago a tennis player, in a casual chat, picked three stars of his generation in his list of the top five greatest players and barely had room for Federer who was then at his peak.
I thought he was on medication. He might think the same when I state that after perusing Serena-Graf stats all morning I have concluded that Monica Seles is my greatest. In the time just before her stabbing in 1993, she had beaten Graf in three of their last four Grand Slam duels.
Only the dull are inflexible and so last year my greatest was Serena. Next year, who knows? Probably Navratilova. In the list of longest match-win streaks, Navratilova is first with 74 straight wins in 1984. In the list of the best win-loss record in a single season she leads with a 86-1 run in 1983. Before you applaud her please note that Helen Wills Moody didn't lose a match, or a set, during a 180-match winning streak between 1927-33. In all our modern delirium over Grand Slam titles do all these other statistics become irrelevant?
Federer who is possibly, arguably, perhaps and maybe the greatest ever always provides perspective. "We probably chase more the records than they used to in the past," he said at Wimbledon. "Keeps us on tour longer." He is 34 and competing; Borg was 26 and retired, having played a solitary Australian Open. How do we measure them?
This week we're busy comparing Serena with Graf, even though Serena is going to pass 22 slams - you dare doubt it? - and Graf fans will insist she's still not better and this argument will endure as long as a John Isner match at Wimbledon. Right now everyone is throwing numerals at each other.
Graf won four slams in a row and an Olympic gold in 1988; Serena twice won four slams in a row but never in the same year. Graf has four of the top 10 best win-loss seasons in history, Serena has one. The American has a serve which John McEnroe calls "the single greatest weapon" ever in women's tennis, but that's because time has muddied our memory of the percussive nature of the German's forehand which flashed from her hip faster than Wild Bill Hickock. Maybe we should call this a draw.
But in truth what becomes rooted in the memory is not titles won or win-loss records or streaks but a portrait of the athlete at work. Serena's greatness may be translated via numerals into record books but her beauty lies in her intensity and it has no measure. It can only be felt.
Even as she ages and gets injured, and has her heart broken by Roberta Vinci at the 2015 US Open, she heals and returns and fights like an unstoppable force. In 2009 in Australia she said "you should never be surprised by anything that I do" and yet how can you not be?
You may not like her fashion choices, her press conferences, her occasional conceits, her theatrics, but you can't look away from a player who radiates resolve. What she craves, you can see; what commitment she wears, you can tell; how desperate she is, you will know. She is not playing for you, but she will, every day, every set, guarantee you what you came to see - a contest. She may not be your greatest player but in sport, let us concede, there are few greater spectacles.