A homeless man with a bicycle and a sign hangs around Belfast's Great Victoria Street, haranguing passers-by with curses and threats.
All his worldly goods are strapped to the bike, along with a notice demanding money.
Tourists love him and stop to talk and take his picture, while he blisters them with a lengthy lexicon of swear words.
I spotted him last week in a doorway, sheltering from heavy rain. He couldn't get both himself and the bicycle under cover and had chosen to protect the bike.
He looked half-drowned, with water dripping from his hat and beard, saturating his several coats and sweaters.
I chanced a sympathetic remark and got a volley of oaths in reply: "You think this is bad?'' he said. "You should have been here on the bad days.''
In two sentences, this ragged-trousered philanthropist summed up a dilemma which the great and the good spent several hours debating at the recent Belfast One City conference.
The conference had the theme A City On The Cusp. Its aim was to assess the progress Belfast has made in terms of tourism, arts, commerce and cultural facilities.
Paul Nolan - author of the Peace Monitoring Report - caught the general mood. The city's present attitude is positive; its future looks bright.
But how, he asked, can anyone collect the data to measure this? As one commentator put it, how do you measure a Belfast Buzz?
The answer to that really depends on whether you were here on the bad days.
The troubled years brought the city to its knees; any comparison with that period starts from a base so low as to be meaningless.
And to go back before that time is to travel into another world entirely - a dour, puritanical world, with little entertainment at all other than pubs, and they closed at 10pm and didn't open at all on Sundays.
Making an assessment from these baselines is a comfort to us all. We can tot up the improved tourist figures, admire the new cafes, talk about the craic and congratulate ourselves on what a great little city Belfast has become.
But that's in contrast with the other, darker Belfast that most of us would like to forget.
Comparison with other cities on these islands in not so favourable. Manchester has better shops, Dublin has better stadiums and Edinburgh's historic centre puts to shame our puny efforts at conservation and restoration.
For all the wonders of the new Titanic centre, Liverpool's waterfront development has a lot to teach us. London is in a league of its own. Belfast may have something to cheer about, but let's not shout too soon.
Certainly, there has been great progress in some areas, most obviously the remarkable advance in venues for the performing arts, particularly noticeable in a city that once treated theatre with considerable suspicion, where putting on a play was an occupation meriting danger money.
The Group Theatre was closed to serious drama from 1959 after a row over its refusal to stage Sam Thompson's play Over The Bridge on the grounds that it was "the policy of the directors ... to keep political and religious controversies off our stage".
The Troubles temporarily closed the Grand Opera House and finally closed the Arts Theatre, leaving the Lyric to carry the torch alone.
I realise I'm in danger here of ignoring my own advice and drawing comparisons only with the dim and dangerous past.
And there is no need of that, for we now have centres for the performing arts which stand comparison with those of any city. The new Lyric, just one year old, has won prizes for its architecture; the MAC is a truly stunning building.
What really matters, of course, are the shows, not the bricks and mortar.
Nevertheless, when you add these stages to the Odyssey, the Waterfront Hall, the Grand Opera House and, on a much smaller scale, The Crescent Arts Centre, it is clear that Belfast is now a city at home with the performing arts, with a welcome on its mat for live production.
There's no finer example than the Cathedral Quarter Arts Festival, now in its 13th year and better than ever.
With jazz and blues and classical music, comedy, drama, the visual arts and a brass band for good measure, can you think of another festival anywhere that presents such an eclectic mix and with such a high standard? Well, I can: the Queen's Festival - and that's ours, too.
Belfast is growing in confidence. Not the defiant swagger of the poor - we always had that, revelling in hardship and an ability to overcome obstacles.
Now there's a real belief in the value of our own achievements.
Some of these, like Titanic Belfast, are world-beaters, as the ship itself was.
But mostly it's the normal things we should celebrate; nice restaurants, good museums, a fine art gallery and a pleasant lifestyle with traffic that mostly flows freely and places of leisure that are rarely packed.
So how do you measure a Belfast Buzz? By its comfortable background noise. For a buzz is a quiet sound, after all.
It's a measure of success. And you don't have to have been here on the bad days to know it.