All good points and I think I see what Vagrant is trying to say. I don't think he literally meant that we should delude ourselves into thinking everyone isn't going to hurt us but that we should not view human nature to be quite as hostile and learn to be a bit trusting because in the end, the benefits can outweigh the risks. Coping mechanisms are great and all but they usually leave more to be desired. For example, I am an incredibly sensitive person so I learned how to disengage most of the time but now it makes the world feel black and white (blah). I think emotions add a little color.
As with everything, it's finding a balance.
I believe people are generally good spirited and I try not to tar and feather the whole species because of the behavior of one or two people.
Emotions don't just add color, they are essential.
They are like a Horse.. You can catch a wild horse and keep it. You can put it in a pen, but It will get out and it might kick a few people during it's escape. Riding it is totally dangerous.
But if you tame and train it, It's become a symbiotic relationship and, during the hard times, it's actually your horse (emotions) that carries you and does all the hard work. You horse will protect you.
Now think about traveling long distance without the horse. Try pulling the plow yourself. Or see how fast you can flee a pack of Coyotes on foot, or better, watch your horse scare them away.
Tame your emotions and they serve you better than not having them or leaving them to fester in the wild of your inner-scape .