It has helped me when people told me that what I believed was incorrect. And you’re right Malvok, there are varying degrees of insight. But, if you notice someone is unshaken in a view it could just be something they chose to believe, as many people with schizophrenia just happen to be more eccentric than most. But pointing out a delusion is the most difficult thing to do, you have to be able to be non-aggressive if you choose to even approach it. I think also, pointing toward something else that grounds someone in reality is the most helpful. Instead of saying outright that someone is delusional, offer advice and practical solutions.
I would say to mcxmac, please stay!