There is a big difference between general optimism and delusion. General optimism is an outlook that looks for things to improve. It is an expectation and a hope that things, with effort and work can improve.
The delusion is having the idea that things are good when they’re really are not. That’s not optimistic. That’s fooling yourself. That’s a lie that you tell yourself. When you see some government program that does nothing but was originally instituted for some noble purpose and you think that therefore, it is something good; that is a delusion. That is not being optimistic.