Every time I watch him, even on his quiet days, there are moments when you just go 'how does he do that?' He does things three or four times in one game that I probably never managed once in my entire career. He does things no-one else can.

I had exactly the same reaction recently when I watched 'The Last Dance', the documentary about Michael Jordan. I'm not a basketball fan and have never followed it but I loved that series and you could see Jordan's absolute greatness shine through.

Jordan is a very different personality, and much more outgoing, but you could describe Messi in the same way - as an icon whose impact and ability far transcends his own sport. In the same way you don't have to appreciate basketball to appreciate Jordan, you do not have to be a football fan to get pure joy from watching Messi.
Like Jordan, he is simply the greatest to have ever played the game - this is why.
People can make a case for other players being better than Messi in certain areas - for example that Cristiano Ronaldo is a better goalscorer. I would beg to differ, but I can at least understand that argument because there's not much in it in terms of their raw numbers, which are pretty much a goal a game.
But it's not just about Messi's staggering goalscoring statistics. An extraordinary combination of things makes him a complete one-off.
Messi is also right up there with Diego Maradona as the best dribbler there has been, because they both have the ability to ride tackles and get out of unbelievably difficult situations with people all around them.

On top of that, he's also quite possibly the best passer of the ball we have ever seen - he sees things that ordinary mortals don't. It's like he's watching the game from above while playing it at the same time, but even that doesn't do full justice to his genius.
I've watched many games of his at the Nou Camp covering Barcelona in the Champions League and there have been many times when I've seen him hit passes that I and the people around me did not see, and that's when we're overlooking the pitch from high up.

To have that vision and awareness on top of everything else is what makes him incomparable as a player, and such a bewildering talent. Yes, he is a brilliant finisher too, and bends the ball into the top corner of the net regularly himself, but if there's a pass on, he'll play it if that's the right thing to do.

He's not just unselfish, his decision-making ability is exceptional. No-one else does the things he does, the way he does them - and no-one ever has done.

His imagination and skills are unique, but there are other reasons we should cherish Messi while we can, which make him such a great example for everyone to follow.
Messi brings joy to the football pitch - he doesn't play-act or dive and he doesn't remonstrate with referees very often or retaliate to any of the rough treatment he gets.

He benefits, of course, from the law changes that were made some time ago to stop people just hacking the greats down - which is what happened to Maradona, for example.
But the amount of games Messi has played is still amazing, because of the paucity of injuries he has had. He and Cristiano Ronaldo are remarkable creatures in that respect.
That means longevity is another part of the Lionel Messi legend, because he's been doing all this since he was a teenager and he turns 33 in June.

We are spoilt to have had him so good for so long and that is down to his spirit, his character and his drive to stay at the very summit of his sport.

Perhaps Ronaldo's greatness has helped there as well, because they have obviously pushed each other on to even greater heights over the years. But there have never been any off-field issues to distract Messi, unlike the chaos that often surrounded Maradona at his peak, and he belies the myth that geniuses have flaws.

Messi is an interesting personality in a different way, of course, in that he is so introverted. For more read https://www.bbc.com/sport/football/52827428