Indications that Shane Byrne might return to racing caused more than a tremble of anticipation among racing fans at the end of last year.

That the most successful Bennetts British Superbike rider of all time might, once again, be mixing it with the pretenders to his throne must also have brought joy to the wallet of promoter MSVR.

But while there is no doubt the 42-year-old, six-time BSB Champion is finding it hard to contemplate retirement - especially when he can see auld enemy Josh Brookes in his team and on the bike that would have been his - it depends on the medics and, at best, is unlikely to be sooner than mid-season.

And alongside the enthusiasm of fans and promoters should be the question: ”Shane, do you think this is a good idea?” A testing crash at Snetterton when he slid head-first into a barrier caused severe damage to his neck and shoulders, ending his challenge for a seventh title in 2018. And, a majority thought, a great career.

The question being asked of Byrne, and undoubtedly one he is asking himself, is the same one being faced by John McGuinness and Ian Hutchinson, two of the greatest TT riders of all time. Why do it?

Following a horrible crash at the North West 200 in 2017, from which the Morecambe man was lucky to escape with his life, McGuinness made one of the greatest motorcycling comebacks of all time to win the Senior Classic TT in 2018.

Now he’s signed up with Norton for the 2019 Isle of Man proper and may ride at the North West in May. At the age of 46 and with 24 TT wins behind you, and not being short of a bob, why do it?

Ian Hutchinson, with a mere 39 years behind him, has won the TT 16 times - an unprecedented five of those being in one week in 2010. But in that same year a crash in a Supersport race at Silverstone left him lucky to survive with both legs in tact.

There was little strength or movement in a badly broken left one which surgeons wished to remove, had Hutchinson let them. Seven years and more than 30 operations of later a crash on the Mountain broke the same left leg. Now he has re-signed up with Honda to do it all over again. Why do it?

Michael Dunlop is another. Now 29, it is not Dunlop who has suffered serious injury but family tragedy, greater than any of the above. His father Robert was killed at the North West 200 in 2010, his uncle  Joey killed in Estonia in 2000 and brother William during practice at Skerries in 2018.

It has now been announced that, after a period of consideration, Michael will resume his career with Philip Neill’s Tyco BMW team attempting to win his 19th TT - or more. Why do it?

The answer will be different for everyone but it is unlikely that money is the absolute driver. It cannot be ignored, though, as they have the opportunity to earn more in one week in the Isle of Man than an entire year on the main land.

But it is doubtful that is the sole motivation. Even in the most successful TT week of all time, scoring five wins, Ian Hutchinson took home less than £100k.

So what is it? For many, especially those from Ireland where road racing reigns supreme, it is a way of life. For those and others it is an annual pilgrimage to the greatest circuit in the world, a supreme challenge, the peak of their year.

For the top echelon, those who ride a full season and are capable of winning, it is the same addictive drug which grabs all who taste success - there is no substitute for the rush gained from standing on the podium or, better still, being on the top step.

It’s what footballers get when they score, golfers when they hole a vital putt. There is nothing like it in normal life  and it is difficult, if not impossible, to give it up. Those who haven’t tasted it will never understand. Superbike king Jonathan Rea says the feeling of winning a race is better than winning a world title...

The one ingredient which defies reason or risk in everything we do, while accepting it exists, is the belief that ‘it can never happen to me’.  

This, plus the combination of an equally-strong belief that success is possible again, makes the lure almost irresistible. Remember Mike Hailwood in 1978?