It's the way he wears his slouch. The way he holds his fork. Whatever. There's something about Damien Duff.
Some absent-minded harum scarum quality that meant the only thing he could ever be in life was a baggy shorted winger, something about him that makes everyone feel as if they know him.
Yesterday he walked into a press conference in a airless room in a hotel in Barcelona and straightaway the atmosphere loosened and it felt like siesta time.
"Yo Duffer!" said a few hacks and Duffer smiled his sleepy smile.
"How's it goin' lads? Alright?"
And for the next 20 minutes or so Duffer is good value. The kid from Ballyboden isn't as shy as he used to be. He has more than soccer cliches in his head.
Does Graham Souness wear a tracksuit and take training?
"Ah yeah. He's out every day, throwing a few shapes."
What about allegations of Souness being anti Irish?
"When I first heard about it I thought maybe I'd be on my way as well, so I was worried. I've found out it's a load of crap really. Like there were a few stories about me beating up people in nightclubs! (laughs sleepily.) They're crap too."
And Roy Keane, has he had an influence?
"He doesn't say a lot, he doesn't have to, he's just a legend. Even if you just get that glare off him on the pitch, you'd do anything for him on the pitch or off the pitch."
It's a few years now since his senior debut in Olomouc in the Czech Republic when he came on and tried to end wing play forever by beating everyone twice on his way to goal.
It was exhilarating and secretly we've clamoured for him to be given a jersey ever since, but, as he admits himself, he was some way off being the finished article.
"I'm cleverer now and I'm stronger," he says. "First division people don't think it's great, but it's a tough league we play in at Blackburn. I've improved as a player. I haven't started an international in a couple of years but I think I'm ready.
"I've lost over a stone. I played all last season 14 lbs heavier than I am. I got player of the season last year even with being a fat oul yoke but I do feel better.
"I feel great. Just happy to be here with the lads. I've worked hard all week in training and I'm still young so it's great to just be involved. I got 10 minutes on Saturday, would have liked more but."
The weight loss has made him faster and jiggier, but if you're waiting on the Duffer Diet book and video you'd better dig in for the long haul. It was a no-guru, no-method job.
"I was getting a lot of slagging from the lads. I'm just a big eater, not a drinker. I wouldn't be out tearing up the town or anything. I just lost a lot of weight by just eating less. I'd get a lot of slagging at training for eating big mountains of food. I've cut that in half."
It's evident that the main hunger in him these days is for a place in the starting XI on the national team. He has been in sublime form for Blackburn lately, scoring one of the goals of the season against Birmingham a couple of weeks ago.
Even so, he is punctilious about observing the pecking order. There is one seat and several candidates for the left of midfield position.
"Yeah. It's been like that for a couple of years now. Kev (Kevin Kilbane) is deservedly number one in that spot."
His career thus far has been an odd thing, full of light and promise but somehow never quite getting the reward that his skills merit. Duff only turned 22 a few weeks ago but he has seen down half a dozen managers at Blackburn Rovers.
It's four years since he was perhaps the best player on view in Malaysia at the World Youth Cup. He made a little history by playing in the competition again two years later in Nigeria.
Most of his Malaysian team-mates have dropped out of the race for stardom, several of the Nigeria squad, most notably Robbie Keane, have overtaken him however.
Yet the feeling persists that, in the long run, when Damien Duff hits the Premiership again, he will be the pre-eminent Irish star of the next decade.
This afternoon he gets the chance to showcase himself again. This long stretch since he emerged in Malaysia may yet be just prologue.
