Basically: do they exist?

Has anyone ever come across a dog whose behaviour was so extreme and intractable that it remained a problem no matter what management techniques were employed?

I ask because I find the current crop of 'dog' programmes a bit unconvincing - similar to those 'nanny' programmes were deep-rooted family behaviours are apparently sorted out by a couple of visits from an 'expert' I have much more experience with humans than dogs and it leads me to believe it's not quite that easy (although I accept the premise that most entrenched behaviour has its roots in early experience rather than inherent tendencies).

Any views out there?

There ARE dogs, like people, who are born with or develop mental conditions etc which impact on their ability to cope with life.  These dogs can never be cured; some can be "managed" in the right environment and in the right hands and some, unfortunately, are just not capable of being homed successfully and either spend the rest of their lives in prison (ie one of the dog charity homes/shelters) or, more humanely in my personal belief, are PTS which puts them out of the constant stress they are under.

I have not only met them I have actually owned one........

Yes they do exist - I own one.  He was in rescue because of his inability to deal with other dogs (and cats), children and some people.  Despite employing various professionals I was finally advised that some dogs - this one included - can't ever change their behaviour.

I have managed to improve him somewhat but he has some serious aggression problems.  Not all of these are possibly his fault as he has an aversion to feet and newspapers so I suspect he has probably been whacked at some point which hasn't helped.

I can only manage his behaviour in a way that I continue to train, train, train and avoid other animals and tricky situations where possible.  If children are around I muzzle him.  It's not an answer to the problem but it's what I have to do. I have no doubt that were I to send him back to rescue he would end up there for ever or be put down.  Thankfully because of my own situation I am able to keep him but he is a challenge.

CG

I know of a Westie puppy at the moment that unless the owner gets a grip is going to be a serious problem :( It came into puppy classes aged 14 weeks ready to take on all comers (including a Staffie),shows no submissive behaviour at all, and has never been to 'puppy play groups' so I can only assume this behaviour has been inherited from poor breeding stock :( The dog itself is large for a Westie pup, and has a cream coat rather than white :(

I foster dogs for a couple of local rescues and can say yes 'problem dogs' do exist. However i believe as with most 'problem children' the reason they are problems is due to upbringing.
There are dogs (and of course humans) who have mental health problems or illness which result in aggression or other 'problem' behaviour but as has been said above these are few and far between and can often be managed with medication.
Just before i had my baby i fostered a labrador - she was beautiful to look at but was a devil at only a year old having been in 4 homes already. Her problems started when her breeder allowed her to be homed at 5 weeks to a family with no idea how to care for a dog - they couldn't cope and she was found a new home - then another -then another then another!!
I think most of these behaviour shows on tv highlight the fact that the dogs problems are caused by their owners. If i see one more person treating their dog like a baby, dressing it up in daft clothes or not taking an active dog like a lab for a walk - i am likely to scream as the lack of common sense frustrates me!!