Allow me to present a sort of a pickle I'm in.
I've believed for a long time that optimism is strictly more beneficial than pessimism. Assuming that you're not sacrificing realism, of course, it seems self-evident to me that we will be happier, stronger people if we try to adopt positive outlooks. Extrapolating on this view, I can see no advantage to anger, or holding grudges, or dwelling on misfortune-- what does it gain us to allow things in our lives to make us unhappy?
For this reason, I tend to argue that, given the option to stew over irritation at people we don't like, or an issue we wish we could escape, it will always be better to just let it go. Let it roll off your back-- like a duck, as my sixth grade teacher once told me.
I also believe that negativity often works as a self-fulfilling prophecy. If you are convinced that things are going to go wrong, or that you're going to have a terrible day, it is much more likely to be true. Focusing on the bad in the world makes it all the more apparent, until it truly does seem that that's all there is to see.
But here's the truth. I'm also incredibly cynical. Sometimes I can't help it, it just happens. The difference is, I don't like being cynical, so being optimistic takes an effort. But this weird disparity means I'm having a hard time approaching the question analytically. Like I said, the logic of optimism seems self-evident to me. But why is it bad to be angry and cynical? After all, the world isn't always rainbows and muffins. So optimists are going to experience more disappointment as compared to pessimists. Besides, negativity doesn't actually harm us, does it? If anything, it makes us more resilient to the terrible things that will inevitably happen, because we won't be caught completely off guard when fate decides to have a laugh at us. We will have seen it coming.
But that doesn't sound right to me either! I think negativity does weaken us, but I'm not at all sure why. Optimists, help me out. What are the concrete benefits to looking on the bright side of life? Pessimists, argue with me. Is being prepared for the worst worth the cost of viewing the world as even more of a dark, miserable place than it actually is?
Some food for thought:
"Holding on to anger is like grasping a hot coal with the intent of throwing it at someone else; you are the one who gets burned."
-The Buddha
"A pessimist is correct oftener than an optimist, but an optimist has more fun, and neither can stop the march of events."
-Robert A Heinlein
"I was thinking that it might do some good if we robbed the cynics, and took all their food. That way, what they believe will have taken place, and we'll give it to everybody who has some faith."
-Jewel