If there is one thing politicians do not trust it is the voters.
Their behaviour is unpredictable, particularly in the polling booths, they refuse to listen to your reason and they often know more about the real state of the nation than you do
They also have a horrible habit of ripping large chunks out of you whenever you are unfortunate enough to come across them in the street.
And that is exactly what Sharron Storer did to Tony Blair as he engaged in one of his few meet-the-people walkabouts of the election campaign.
The prime minister was left speechless as Ms Storer tore into him over the state of the NHS and, particularly, the tragic case of her partner.
The prime minister was left with that Women's' Institute look on his face - the one that suggests he doesn't know how to respond to criticism from real people and which appears to ask of his spin doctors "how did you let that happen."
He spluttered his apologies a couple of times and then, clearly worried about the way this assault was going to look on TV, attempted time and again to get his tormentor to "come inside and discuss it with me."
The doughty Ms Storer refused and, having forcibly made her case, pushed past him and went on her way, patently unconvinced.
It is exactly this sort of confrontation with voters that politicians have recently attempted to avoid.
Mr Blair has already faced criticism for carrying out his campaign from within a hermetically-sealed glass jar.
And his clash with Ms Storer shows precisely why his aides are determined to keep him away from the public - they just refuse to stay on message.
And the timing, on the same day Mr Blair unveiled Labour's election manifesto, could not have been worse.
However, it would be hugely unfair to suggest Mr Blair is alone in his voterphobia.
Probably the most famous recent occasion of a politician being dramatically put on the spot by a voter was during the 1983 election campaign.
During a televised phone-in, the then prime minister Margaret Thatcher was challenged time and again by geography teacher Diana Gould over the sinking of the Argentine warship General Belgrano at the start of the Falklands war.
Mrs Thatcher was left looking evasive and disingenuous as she persistently refused to confirm that the ship had been sailing away from a confrontation at the time she ordered its sinking.
The clash clearly rattled her and the issue dogged her for the rest of her career as prime minister.
Back of lorries
So it is no surprise that, in the days of ultraspin and politicians' desire never to look foolish, they fight shy of such confrontations.
It was not always like this of course. Up until the 1983 election campaign it was the rule for politicians to go out on the stump meeting voters and making speeches from the back of lorries.
They were regularly heckled and abused and confrontation was all part of the package - some even revelled in it all.
Then, as the US way of campaigning took greater hold in Britain, things changed and the next three elections were tightly controlled media events.
John Major tried to break the mould with his soap box in 1997 and immediately ran into trouble on his first outing in Luton. He handled it pretty well enough but there was still a huge reluctance to put leaders back in the firing line.
That started to change this year with both Charles Kennedy and William Hague apparently believing the only way they could dent Labour's huge poll advantage was by meeting as many voters as possible.
By contrast, the Blair campaign looked remote and fearful. But look what happened when he broke out.
Coincidentally, just as the prime minister must have been pondering the advisability of his walk on the wild side, his home secretary Jack Straw was being monstered by the Police Federation as he addressed their annual conference.
Suddenly all Labour's most carefully laid plans for manifesto day looked like they were starting to unravel.
You just can't trust voters - or the police for that matter.