Temper
"If I've played badly, of course I'm going to get angry with myself or frustrated. But I still think I'm pretty good at leaving it on the golf course."
Well maybe not that good. In September a fit of pique saw him not only smash the head off his driver at the BMW Championship, but also subsequently put his foot through a locker door on his return to the clubhouse. Coach Cowan believes his aggressive streak is a crucial part of his make-up, but feels it too can be worked on if Stenson is to go on and achieve his newly-redefined goals.
"He is one of my players that I have to have a strong word with now and again, and I give it to him straight," explains Cowan. "If he has one minor weakness it's his temper, his temper is still a fraction up, but I think that's a plus in a lot of cases because that gives him the strength to commit more and move harder at the ball."
So what of Stenson's objectives? Where does the 37-year-old go after a summer of such unprecedented success?
Henrik Stenson targets a major win in 2014
The Swede, like everyone who has witnessed his ball-striking mastery this season, concedes that a major championship would be the logical step, describing it as the "one thing missing".
With seven top-10s since 2008 Stenson is certainly no stranger to contending in the big four, but there now seems certain to be a different kind of pressure on him when he tees up in those tournaments in 2014.
But rather than let expectation weigh him down, Stenson is likely to relish the challenge his status brings following his trials and tribulations. Two summers ago, and with no invitation to the USPGA Championship, Stenson opted instead to enter a competition at his local course in Barseback with dad Ingemar on his bag... and finished second to a member.
Skip forward almost exactly 12 months and he would finish as runner-up again, only this time to slightly more acclaim as it came behind an inspired Phil Mickelson at Muirfield.
"When you're that close to winning a major championship and still feeling like you've got a spare gear when everything is working, then that's exciting," Stenson would comment that weekend in Scotland.
But if you thought the Swede had discovered that extra gear in completing his extraordinary transatlantic double, think again.
Ian Poulter embraces Stenson as he secures the Race to Dubai title and wins their now infamous side bet!
The bad news for Stenson's rivals comes from Cowan, who insists his pupil is still operating some way short of his full potential.
"I'd say his game's only at about 70 percent of where he wants it to be. A major's the only thing missing off his CV now he's done what he's done this year. He said to me he's got one in him so why shouldn't he win one?"
Very few, if any, in golf would bet against him... with the exception, maybe, of Ian Poulter.