Pardon me while I wax philosophical for a moment.
There are a lot of catchy clichés describing how optimism is the light of the world, and how pessimism is evil creeping into your thinking. Seeing a glass as half empty, though, is not a negative outlook. It’s a realistic assessment of a limited resource.
This is a companion discussion topic for the original entry at https://brettterpstra.com/2015/07/24/in-defense-of-pessimism