Is there such a thing as too much self-esteem? Psychologists would have us believe that you can never have enough of it. The problem with our society, they moan, is that there are too many sources for depression and self-loathing. We are surrounded by images of success and wealth which we can never hope to live up to. No wonder teenagers with a dozen A+ grades at GCSE feel suicidal: there's nothing more that is ever any good enough for us. We must learn to protect our fragile inner child.
This attitude does not explain the stratospheric self-regard of the thousands of X Factor contestants now parading their talentlessness on ITV1 every Saturday night. Simon Cowell's new show in the Pop Idol mould is a celebration of monumentally groundless self-belief.
"I know I've got it," weeps the chicken factory employee with the voice of a dying Smurf. "It's their loss, not mine," screeches the page-three throwback with no discernible gift for entertainment, vocal or otherwise.
When they are rejected, the puffed-up audition participants storm off to a private room where, alone, they vent their indignation to a camera. Sobbing, many of them utter the phrase, "But I really have got the X factor." Most believe the judges to be completely insane: deaf and blind to their unmissable, sparkling charisma. They are distraught not to go through to the next round - distraught not at the merited criticism, but at the injustice of it all. Most of them genuinely think there has been a terrible mistake.
This unquestioning self-love knows no bounds of race, age or gender. Spotty teenagers from Woking who believe they are the next Eminem and ageing hippies after that one last chance are as one in their refusal to let the dream die. The problem is that their talent is just that - a dream. They don't really have any. The truth would hurt - if there was any danger of the contestants coming anywhere near it. Instead, they cling stubbornly to their flawed estimation of themselves.
Nobody deserves to think that they are worthless or that they cannot achieve anything in life. But is it not cruel and wasteful to maintain the deception that we can all attain riches, power and glory far beyond our capabilities?
In accepting the American ideal that, in the words of the song chosen by so many X Factor contestants, "If I just believe it, there's nothing to it", we are colluding in a delusion on a gigantic scale. R Kelly may believe he can fly, but the rest of us should embrace the sparse comforts of life's departure lounge.
The problem is, public life is littered with people who quite literally believe they can touch the sky if only they believe hard enough. Step forward George W Bush, Victoria Beckham, Jordan, Michael Winner. All suffer from an overdose of self-esteem. They would happily attempt to disprove the existence of gravity rather than embrace quiet mediocrity.
If these people's unshakeable self-belief could be bottled, there would be no market for Prozac. Politicians are perhaps the worst offenders, especially around party conference time. They never utter a whisper hinting that there is even a possibility of them not winning an election.
This is textbook therapy. Act like a winner and the next thing you know, you'll be one! Or, to put it another way: love me - I do.
When I was young this was called "showing off". Nobody likes a show-off, we were repeatedly told. In fact, children constitute the one group of the popula-tion that should be allowed to love itself as much as it wants.
All adults should in turn embrace self-effacing modesty. A consummate offender in the past, Madonna is in the vanguard here. (It should be pointed out, however, that it still requires a hefty dose of self-esteem to force everyone who addresses you to wear white just because you have become a follower of the Kabbalah cult.)
She said recently that in some ways she regrets the earlier stages of her career: "I was just showing off." Take it from her, some of us really would be better off hiding our light under a bushel. Try telling that to the X Factor crowd, or to the millions who buy self-help books.
The truth is, too much self-belief is dangerous for our mental health. The psychobabblers who encourage us to reach for the stars should remind us to love ourselves a little bit less.
As you may remember from one memorable episode of Frasier, the therapist's arch-rival Dr Nora upbraids him for raising the morale of the losers who phone in to his radio show: "You tell tramps and fornicators they have low self-esteem. They should have low self-esteem - they're going to hell."