I don't think anyone knows everything there is to know about being human. Who does? People often act as if they know everything or at least know better, even when they shouldn't.
But most people have okay coping skills as tragedy was common place for hundreds of thousands of years. Using the same strategies can re-victimize them. Think of PTSD. The problem with PTSD is an inability of the mind to let go--a person is always reliving the moment in terms of stressfulness, if not literal imagery and thoughts. Forcing someone to sit in a room and discuss a tragic experience whose memory of the experience has already, naturally begun to fade into the background is its own tragedy.
That's my $0.02. Maybe I'm just naive.
Welcome to the human condition!
In the list of intentional homicides Sri Lanka indeed ranks higher than I expected, rank 132 of 230: https://en.wikipedia.org/wiki/List_of_countries_by_intention...
About being calm: I agree about the anger on roads. Except for that my impression was a calm and peaceful one -- maybe what you encounter as violent is still OK from my culturally distinct perspective? Do you think there are many 'fights'/arguments where people are shouting in the public, or would such a thing happen at home?
And what is your opinion about the high suicide rate?
There are many fights and tense situations, but more in places like inner city Colombo than in Kandy or Galle.
RE: suicide: hard to say. Our alcohol consumption and suicide stats are both extremely high. But even after living here all my life, it's hard to pin down a theory about why this is. My personal belief is that the average Sri Lankan's belief in Karma and astrological fate results in a defeatist attitude. We often hear the phrase "I/he/she probably did something in a past life to deserve this" in reference to tragedy, hardship or misfortune.
the people are very calm and nice to each other and to Tourists, it was a pleasure to travel around. It's a very safe place, crime and stealing is almost nonexistent. Disagreements are solved in a quite calm way.
You may have seen a tourist's version of the island, and have been fortunate enough to not encounter violence or theft. Both are very common. People are very quick to anger on the road. Theft and flouting rules are common. Don't get me wrong, we have many good qualities (for example, we're known for being helpful and hospitable), but calmness is not one of them!