In Baghdad, the most common sound you hear in the streets today is the insistent racket of small private generators.
The most common sight, apart from police and army roadblocks, are the black banners on walls and fences announcing people's deaths.
And the most common feeling you come across is a kind of slow-burning, gloomy anger.
Iraqi commandos and US military advisors now patrol Haifa Street
These things represent a major failure of the hopes and expectations which many Iraqis entertained four years ago.
The generators are there because the Americans and successive Iraqi governments have failed to sort out the power situation. And the deaths happen because they have not established peace here.
'They will help us'
It is easy to forget how high the expectations once were.
"I don't like the feeling that my country has been invaded," a shopkeeper in Haifa Street told me, a day or so after the fall of Baghdad.
"But thanks to God that it is the Americans who have done this. They are the richest country on earth. They will help us."
But they did not. They did not even protect the ministries and public buildings and museums from being looted.
We filmed as people shouted "Do something!" at an American soldier, while thieves were running out with valuable medical equipment from the hospital behind us. He just shrugged his shoulders and turned away.
Iraqis were infuriated by the gross mismanagement and open theft that American contractors and Iraqi politicians carried out in the first year after the invasion.
They had little but contempt for the feeble administration of Paul Bremer, the American proconsul whose only previous senior job had been as US ambassador to the Netherlands.
Then and now
When I went to see the shopkeeper in Haifa Street in May 2003, I walked there on my own.
There was the occasional rattle of small-arms fire, and groups of people sometimes looked at me angrily. But I did not feel my life was in any kind of danger.
Baghdad hospitals routinely deal with those injured in suicide attacks
A couple of days ago I went back to Haifa Street. It has recently been the scene of a series of battles, with Sunni gunmen being winkled out of their positions by the Americans and the Iraqi army.
It is difficult for an unarmed Westerner to go there now, and I had to travel in an unmarked van with dark curtains at the windows and two British security men to protect me.
The shopkeeper I had met four years before had long gone. There was no-one to ask: all the other shops in the row had closed down as well.
Early next day, I went to film at a big city hospital. During the hour I was there, six bodies, found in the streets that morning, were brought in. All had obviously been tortured, and one had had his feet sawn off. It was just a normal morning.
After Baghdad fell, I would satellite reports back to London about attacks in which one or two people were killed. It was big news in those days. Last Thursday, a bomb exploded near the end of the street in central Baghdad where the BBC has its office. Eight people were killed and 25 injured, and we had rather good pictures of it.
But I did not ring London to offer a report about it. To get on the news, or the front page of the newspapers nowadays, a lot of people have to die. I would say the current figure is 60 or 70; and it certainly wouldn't be the lead.
This is not because editors do not care; it is because it happens so often it scarcely seems like news.
Cynicism and anger
After four years of occupation, this is a dangerous, callous, frightened, anxious city.
Its people are wearily sceptical about the current dip in violence which the current American troop "surge" seems to have brought.
They mostly believe that the various warring militia will keep their heads down while the surge lasts, then come out again when the Americans have left.
Two separate bombs in Baghdad killed at least 10 on Thursday
But cynicism and anger are not the only emotions.
At the hospital I visited, I interviewed a vascular surgeon who had succeeding in patching up a young girl's arm after a bomb attack.
"You must get sick of all this," I said. "Are you tempted to leave the country, like so many of your colleagues have?"
"No," he answered, "Even if I knew I was going to be killed tomorrow, I would stay here. It's my duty."
One day, that kind of attitude will turn this back into a vibrant, effective country again. But it will not happen for a while.