Gordon Strachan's theory, expounded with characteristic diffidence, is that in most organisations, indeed most professions, there are basically three kinds of people.
"You have the top, top guys, the brilliant few. You have the good solid pros, who are the majority. And you have two or three who cause problems out of all proportion to their worth," says the Middlesbrough manager.
"Take your business, the media. People think I've got a problem with the press. Actually I have no problem with the press, but just like in football there are a handful who cause problems because they're disrespectful, they're lazy, and above all – and this is what really gets to me – they haven't worked hard to get there.
"I can sit in a press conference with 30 people and there'll be two or three who one way or another just shouldn't be in that room and I think that was particularly the case at Celtic.
"It took me 35 years of being involved at a decent level of football to become manager at a great club like Celtic. A reporter has been making jingles at a certain radio station one week, and the next is asking me questions about football which I felt were disrespectful to me, given how long I've worked in the game. Just because you're a former morning disc jockey doesn't mean you can be in the same room as me and ask me football questions."
Warming to his theme, Strachan gestures towards the media room at Middlesbrough's splendid training ground in the North Yorkshire countryside, where he has just held a good-natured if customarily idiosyncratic press conference. "The other thing is talking right after games. I gave that a body swerve for a year because I thought people were being disrespectful not only to me but to every manager in the game.
"OK, I might as well say it; I think some channels have become bullies to managers. You make it clear you're making yourself available to talk about the game, not what somebody said three days ago or about transfer speculation. OK, they say, and immediately ask you about a transfer. I'm not having it. I don't like people trying to bully me."
Is that essentially why he left Celtic, after four seasons in which he had won three successive Premier League titles and twice taken the club into the last 16 of the Champions' League? "Oh no. No. It was simply the right thing to do, for the club and myself." Because Celtic's largest shareholder, Dermot Desmond, made it clear there would be no more money for major signings and the club had to be run on a break-even basis? "No. In the time I was there we reduced the club debt from something like £34m to close to zero, and still managed to win one or two trophies. So actually not too bad going, in that respect."
On this occasion the sarcasm is gentle. On others, particularly those when Strachan feels he has been, like the Godfather, disrespected somehow, it is anything but. Plenty of journalists have been the subject of an acerbic put-down, which he accepts probably doesn't help when his managerial record is being analysed.
"I think what I've actually achieved as a manager does sometimes get a bit overlooked, because all people think about is the media side of things. They tend to forget I've not done so bad. Keeping Coventry in the Premier League for four or five years on a budget was not a bad job. I'm still quite proud of that, though I did make mistakes there in the end, in not properly replacing Gary [McAllister] and Robbie Keane, and we got relegated.
"Actually I made two mistakes, but the other was a personal thing." He declines to elaborate. "At Southampton I took a club that was second bottom to 11th, then eighth, to a Cup final and into the Uefa Cup. Celtic is recent enough for most people to remember, even certain journalists. But it tends not to get mentioned because of the nonsense which follows me. And perhaps some of that is my own doing." So is Middlesbrough as much about changing perceptions as anything? "Nope. It's because it's something I haven't done before – I don't know this league like I know the Premier League or the SPL. And though I don't love managing, and could live without it, I do love coaching and making good players better.
"Today there were three players in particular I worked with to adjust their technique and they responded, and I feel like it's been really worthwhile. Not youngsters, established players – that's the buzz, right there."
So why not just coach? "Now that's a decent question. I suppose because I like to be able to control which players I'm working with. Because it doesn't matter how good a coach you are if the guys you're working with think they already know it all. You need a response, you need to feel they're trying. I want players who are always striving to improve."
Hence the turnover at Boro since he arrived, and the influx of players from the SPL. "It's not just about ability, it's about hunger and drive, about really hating to lose. Nor is it just a question of money, though you know fine well it's a big part of it.
"Look, if a lad was earning – let's say – £1,400 a week in the SPL, and is given the chance to earn £4,000 in the Championship, he's in dreamland and is going to fight to stay there. But one of the biggest problems is these 18-player match-day squads. It's created monsters, players being paid a fortune just to fill the benches. But because they're in the squad they think they should be playing, and you have unrest in the dressing room, winning or not. I'd love to shed four or five of those wages."
After leaving Celtic, Strachan admits he considered getting involved with issues beyond football. "I get the feeling a lot of politicians are there to help themselves financially, first and foremost. I don't really need to do that, and I thought if I could do something for sport in Scotland, that would be really fulfilling.
"What really gets to me is the lack of provision. I go to Sweden and every community, however small, seems to have its own running track, football pitch, sports centre – and you can do so much with sport. You can educate through sport. I'd like to get involved in something like that, perhaps I will eventually. But my problem is I still love football. When I play five-a-sides with people of my own age, the emotions are still there. I get angry, I laugh.
"After I left Celtic we were on holiday in Florida, and my wife Lesley and I went cycling. Went past a game of football, a team of Puerto Ricans against someone else, Mexicans or Colombians. We were the only spectators and at the end the players came over, asked me if I played. I said yeah, a bit, and we got talking.
"So I don't think I could cut myself off from it altogether. As long as I can talk about it and laugh about it I'll be all right. But I have to laugh about it."
Famous Strachan Exchanges
Reporter: Welcome to Southampton. Do you think you are the right man to turn the club around?
Strachan: No, they should have got George Graham. I'm useless.
Reporter: There goes the unbeaten run. Can you take it?
Strachan: No, I'm going to crumble like a wreck. I'll go home, become an alcoholic, and maybe jump off a bridge. I think I can take it, yeah.
Reporter (after a win): You must be delighted with that result? Strachan: Oh, spot on. You can read me like a book.
Reporter: You don't take losing lightly, do you?
Strachan: I don't take stupid questions lightly either.
Reporter: What is the situation with [unhappy player] Agustin Delgado?
Strachan: I've got more important things to think about. I've got a yoghurt to eat, the expiry date is today. That's my priority.
Reporter: In what areas were the opposition better than you today? Strachan: Mainly the big green one out there.
Female reporter: Can you explain what went wrong today?
Strachan: Explaining it to you is impossible. It would be like you trying to explain childbirth to me.
Life and times
Dundee 1974-77: 60 games, 13 goals.
Aberdeen 1977-84: 187 games, 55 goals; won two Scottish League titles, three Scottish Cups, the European Cup-Winners’ Cup and European Super Cup with Alex Ferguson.
Manchester Utd 1984-89: 160 games, 33 goals, won FA Cup 1985.
Leeds 1989-95: 197 games, 37 goals; won Second Division in 1990 and First Division 1992.
Coventry 1995-97: Player-coach under Ron Atkinson.
Scotland 1980-92: 50 caps, five goals. Played in 1982 and 1986 World Cups.
Coventry: 1996-2001: Three mid-table finishes but relegated in 2001 to end a 34-year stay in top flight.
Southampton 2001-04: FA Cup final 2003 (lost 1-0 to Arsenal). Left for personal reasons.
Celtic 2005-09: Three consecutive League titles but let a sevenpoint lead slip at the end of the 2008 campaign.
Middlesbrough 2009-present: Signed a four year deal in October 2009.