By Mark Barden at Wembley Arena
What exactly goes on inside Ronnie O'Sullivan's head?
It's a question that has baffled snooker fans since "The Rocket" burst onto the scene by winning the 1993 UK Championship aged 17.
Ronnie's got the bit between his teeth - he's on a mission to win this tournament
BBC pundit & former world champion John Parrott
At the same tournament in December, O'Sullivan walked out while trailing 4-1 to Stephen Hendry in the quarter-finals.
He later said "personal problems" were behind his behaviour and admitted: "Snooker has slipped down the pecking order in terms of my focus."
It was the latest in a long list of controversial incidents that have blemished the career of a player viewed by many as the best ever.
So all eyes were on O'Sullivan when he returned to action in the first round of the Saga Insurance Masters at Wembley Arena on Tuesday.
Which Ronnie would turn up to face Ali Carter?
Would it be the bored, disinterested, dispirited version, or the "Essex Exocet" at his brilliant best.
Unfortunately for Carter, it was the latter, and he went on to thrash his former practice partner - who really didn't play that badly - 6-1.
Getting back on the horse at the Masters was always going to suit O'Sullivan, who won the title in 1995 and 2005.
The venue has changed this year, following the demolition of the event's old Conference Centre home, but the Wembley crowd have always loved a bit of flair.
Tuesday afternoon's session attracted a real cross-section - young, old, male, female - and most had come to pay homage to Ronnie.
After a cagey opening four minutes, he didn't disappoint them, capitalising on a missed red by Carter to build a break of 91 to take the first frame.
The game needs Ronnie like it needed Alex Higgins and Jimmy White, and I think Ronnie knows that
Another break of 73 sealed the second, and a brisk run of 106 made it 3-0.
If this was a man lacking focus in his game, he wasn't letting it show as he prowled around the table exuding menace.
Ronnie is no poker-faced pro, however - there's plenty of wincing and face-pulling when he falls short of the perfection he demands of himself.
Carter, the world number 15, pulled a frame back just before the interval to make it 3-1, but gifted his opponent too many opportunities to win another.
A fluffed red let Ronnie in for a winning 64 break in the next, and a bad mistake on the black allowed O'Sullivan to make it 5-1.
Carter, looking slightly shell-shocked by now, repeated the error minutes later and watched helplessly from his chair as Ronnie made a clearance of 92.
He punched the air to acknowledge the raucous applause, signed an autograph and was off - and heading straight for more controversy.
World Snooker's rules oblige all players to talk to the media after a match, but
Ronnie - who could yet be punished for his York walkout - didn't fancy it.
The talking was left to Carter, who hit the nail on the head when he said: "The game needs Ronnie like it needed Alex Higgins and Jimmy White, and I think Ronnie knows that."
He compared O'Sullivan's brand of genius to George Best's, adding: "He's so good, maybe he finds it difficult to balance his private life."
Ronnie did have his say in a brief BBC TV interview with fellow former world champion Steve Davis.
He thanked people for their "fantastic" support, revealed he had only resumed practising a week ago, and that he has a bad cold.
So very little practice, feeling poorly, wins 6-1. Only Ronnie, it seems can really beat Ronnie.