We have just emerged from the most violent century in human history - and the new one is already going bad.
We talk about peace. But time and again, we go to war. Humans make war, dread war, enjoy it, even love it.
War blights lives, it ends them - and it defines them. It's deadly. It can be exciting. It's terrifying and disfiguring.
"Stay there long enough, and you will find your breaking point"
War can be all of those things in a single day.
It sickens me. But the first time I went to a war, in El Salvador in 1989, I was seduced by it too.
I was nervous because I had been watching it on the TV and a lot was happening. It was violent.
But I wanted to prove that I could do it.
When I got there and it was the first day and there was shooting, and I got through it and wasn't killed, then it was fantastically exciting. That was a powerful drug.
Hearing a bullet go by
Jon Steele, who was an ITN cameraman for many years, reacted the same way:
"I actually liked it. It was something about hearing a bullet go by your head... immediately your blood starts to boil and you get tingling in your fingers, and I liked it. I just thought it was cool. You know here I am, I'm in war, I'm in an action movie."
That mixture of fun, fear, excitement, adrenalin fades as time goes by, though it never completely goes away.
For me, at least, the main reason I have reported on 12 wars for the BBC (though I don't do it much anymore) is that it has always felt worthwhile.
Allan Little: Bearing witness in Bosnia, hoping to change things
We were witnesses to some of the worst things that were happening on the planet and it was important to tell people what had happened.
Allan Little, who's now the BBC Paris correspondent, felt that strongly during the Balkan wars of the 1990s, like all of us who were there.
"I think a lot of us, especially in Bosnia, a lot of us thought that the effect of our being there and bearing witness would have a beneficial effect, would in fact change things," he says.
"And it was a profoundly disillusioning experience extended over three or three-and-a-half years for that reason, because in fact, it didn't change anything."
During the Bosnian war I felt more at home in Sarajevo than in London. It felt normal. I didn't have to explain anything to my friends in the Holiday Inn.
It is hard to analyse grand strategy in a slaughterhouse.
To report war and its aftermath properly, you need to start with what it does to people. But war zones distort and pervert normality.
The abnormal becomes routine. Stay there long enough, and you will find your breaking point.
When Fergal Keane was based in Africa, covering the Rwandan genocide in 1994, he started to get the feeling that something was wrong.
"After the genocide in Rwanda, I went through a very, very bad period of dreams and nightmares, questioning, you know waking up at 3am in the morning in a room full of dead people looking at you, dead people sitting at the end of the bed," he says.
"And this was particularly intense over one long summer, the summer after the genocide, and for the first time I became aware of some kind of collateral damage from the job that I was doing."
Reporting wars is very intrusive. You enter people's lives at their worst moments.
A good day for us is always the worst day or the last day for them.
The only justification is that reporting the truth is essential.
Jeremy Bowen On the Front Line was broadcast in the UK on Sunday, 16 January, at 2215 GMT on BBC One.