Big bold ideas that turn out badly receive plenty of critical attention, those that turn out well tend not to receive the attention they deserve.
A big bold idea for the movement of people and traffic in Auckland's central business district is working so well that we already take it for granted.
Walking or driving slowly in some of the side streets we hardly notice that pedestrians and vehicles are mingling without a problem.
Yet five years ago when the former Auckland City Council's urban design group manager, Ludo Campbell-Reid, suggested turning the narrow streets into "shared space", the idea was daringly radical.
It stepped outside the endless debate between those who wanted to close the streets to traffic and the business owners who feared a loss of access for suppliers and customers. We could have both, said Mr Campbell-Reid.
By doing away with footpaths, kerbs and parking spaces and paving the whole corridor in a way that was inviting for pedestrians but not smooth for cars, the city could favour foot traffic without barring vehicles completely.
It was "pro-pedestrian but not anti-car", he said. To those who feared it would cause confusion or worse when cars and walkers were on the same path, he said relax, people would work it out.
So they have. Drivers who need or want to use those streets go slowly when pedestrians are there and the pedestrians move out of their way with hardly a thought.
It works naturally, unremarkably. Like all good solutions it seems so obvious that it goes without saying.
Yet there is a lesson in this experience. Shared streets are not unusual in Europe, as New Zealanders knew long before Mr Campbell-Reid arrived.
Why did it take a Londoner to recognise they would be "a good fit with the New Zealand psyche"?
Perhaps because the practical, easy-going side of our psyche is not the only side.
The other side is uneasy without strict and clear rules for safety and fair sharing.
We do not say "she'll be right" unless the number eight wire is fairly tight and definite.
Even now, those who had the courage to introduce shared streets probably break out in a sweat at times when they consider that sooner or later an accident is likely to happen. They know that if ever someone is injured by an inattentive or angry driver in one of these streets, there will be those who decry them.
But they have been operating without a serious mishap for nearly four years.
Darby St was the first to be converted to shared space in March, 2011, followed by Elliott St in August. Since then, Fort St, O'Connell St and Federal St have been reconstructed on the same principle, as has the new Wynyard Quarter's waterfront promenade.
Not everything has been a runaway success.
Federal St shows that shared space alone is not always enough to make a place pleasant. Despite popular dining spots, entrances to SkyCity's hotels and car parks make the street uninviting.
It is not beyond question, however, that it could yet develop into something much more attractive.
Either way, shared space is an improvement on parked cars and "rat-run" traffic in narrow alleys. Elliott, Fort and O'Connell streets are particularly good.
When will High St wake up?