I don't blame people for being optimistic. We should never do that. But we should be aware how optimism, as well as pessimism, can so easily blind us. There's a quote a like by Feynman

  The first principle is that you must not fool yourself and you are the easiest person to fool.

We need optimism. Optimism gives us hope. It gives us drive.

But we also need pessimism. It lets us be critical. It gives us direction. It tells us what we need to fix.

But unfettered optimism is like going on a drive with no direction. Soon you'll fall off a cliff. And unfettered pessimism won't even get you out the door. What's the point?

You need both if you want to see and explore the world. To build a better future. To live a better life. To... to... just be human. With either extreme, you're just a shell.