The English Premier League is blessed with some of the very best managers in world football.
But time and time again, clubs make poor decisions, appointing so-called "messiahs" that end up doing more damage than good during their tenure.
Whether it's poor transfer targets, wild spending or just a distinct lack of positive results, these men keep finding jobs despite the warning signs being glaringly obvious.
While Sir Alex Ferguson and Arsene Wenger keep raising the bar, the likes of Martin O'Neil and Sam Allardyce continue to be given second and third chances to prove their worth.
Although some of these managers are not currently active, all four continue to be linked with new posts in the near future—more fool the chairmen that employ them.
Here are the leading contenders who should come with a toxic warning...
Harry Redknapp has the best track record in this list but is still severely overrated by many of his peers.
Over the past 20 years, Redknapp has won one Intertoto Cup with West Ham (1999), an FA Cup with Portsmouth (2007) and promotions with Bournemouth (1986-7) and West Ham (2002-3) respectively.
It's hardly the glittering CV many come to think about when discussing his managerial successes.
And while Portsmouth did win the FA Cup, it came at a huge cost—their Premier League status.
Wild spending saw Portsmouth enter into administration, and their plight since has been incredibly sad for such a historic football club.
Getting Spurs into the Champions League was perhaps Redknapp's best achievement to date, but since his subsequent corruption arrest and acquittal, it's been downhill for the 66-year-old.
With the FA preferring Roy Hodgson as England manager, Redknapp was sacked by Daniel Levy after failing to agree to a new contract.
Perhaps surprisingly, Redknapp took the job at Queens Park Rangers under the pretense of having endless funds and plenty of time to beat the drop.
Crazy spending and relegation followed, which have further cast doubts over his managerial attributes.
Once tipped to replace Sir Alex Ferguson at Manchester United, Martin O'Neill's fall from grace has been nothing short of spectacular.
His efforts at Leicester were admirable, but he's been living off that for more than a decade.
Yes, he did well at Celtic, but the Scottish Premier League is equivalent to England's League 1—it's nothing to write home about.
However, his return to England has only seen his stock fall to an almost unemployable level.
During his four years with Villa, he spent over $180 million while only recouping $60 million.
He could not get Villa past the last 32 of the UEFA Cup and left after reported differences over more transfer funds.
Sunderland was hardly the job O'Neill would have hoped for when making his high profile return to management, but he took it regardless.
Again, the wild spending continued as he entered his first full season in charge.
But the dreams turned into nightmares as the Black Cats plummeted down the table at an alarming rate.
Sacked a month ago, Sunderland are now desperately fighting in a relegation dog fight that the Northern Irishman has single-handedly created.
He is now a very risky appointment should another club come calling.
There is no denying that Sam Allardyce did an admirable job at Bolton, but his track record since has been anything but impressive.
The fact that Allardyce continues to manage at the highest level despite his continued lack of achievement is a real head-scratcher.
The 58-year-old is well known for winning ugly and left Bolton in the summer of 2010 due to his desire to win trophies (per The Daily Mail).
Almost six years and three different clubs later, he is still searching for that same silverware.
But there are plenty more pressing things to worry about than chasing a trophy—like winning games!
Allardyce has a losing EPL record for each club he has managed since leaving Bolton, with fan protests becoming a regular occurrence.
He has gone on record as saying his managing style is more suited to Inter Milan, Real Madrid and Manchester United (via The Guardian), but with West Ham's underwhelming season, he should be thankful he's still in a job.
There is no arguing that Hughes was a fantastic player in his day, but as a manager, he's the most overrated in the game.
Hughes' first high profile job was at Manchester City, following decent work at Blackburn and Wales respectively.
But a top-six finish at Ewood Park and just missing out on qualification for Euro 2004 are hardly career highlights.
Much of the media made a big deal out of his being sacked as manager, but looking back at his tenure, he had more than enough time and money to prove his worth.
Hughes spent over $150 million at the Ethihad, bringing in names such as Robinho, Emanuel Adebayor, Roque Santa Cruz, Shaun Wright-Phillips, Wayne Bridge and Jo—I'll leave you to judge how good those signings were.
Instead of consolidating with Fulham, he turned his back on them stating, "As a young ambitious manager, I wish to move on to further my experiences" (BBC Sport).
His ego probably didn't expect his next job to be at QPR, but with incredible financial backing, (he was given the same kind of transfer budget he had at Manchester City) surely he wouldn't make the same mistake twice?
Not only did he repeat the disastrous spending that found him out of a job in Manchester, he relegated a club in less than half a season.
Although others have tried to revive the club since, the damage was done during Hughes' tenure.
He should concentrate on coaching because it's quite apparent that the 49-year-old is the only person who holds himself in high regard as a manager.