Let me make a counterpoint that slipping into delusion isn't necessarily a bad thing--as long as you are aware of it.
Essentially, EVERYTHING is a delusion to some extent. We don't apprehend the "real world" directly, we perceive it through faulty senses and process it through filters of experience and meaning. Whether you realize it or not, you are choosing what to attend to and thereby creating your own personal delusion all the time--and you can do this either passively or actively. When you do it passively, you are falling victim to the delusion and believing it to be reality. When you do it actively, you are participating in what Carlos Castaneda called "folly"--an intentional acting job that molds your reality.
For instance, when I used to have a job in the traditional sense, I would slip into the delusion that my work was important and that my very being (as well as the well-being of those with whom I worked) was dependent upon me being responsible and doing a Good Job at work. But I knew it was a delusion; when I was NOT at work I did not define myself by my job or by how well I did at it. (And believe me, I did well at it. I have sat with State governors and dined in the Senate dining room with the likes of Bob Dole and John Glenn in recognition of my accomplishments.) I hate public speaking, but I can slip into the delusion that I'm good at it when I need to be. I'm not a "people person," but I can slip into the delusion that I am the life of the party, when it benefits me to do so. I found that these states were qualitatively no different than my "natural" delusions that I hated public speaking and that I was not a people person, and I could move between them as needed.
So go ahead, slip into delusions--but be aware of what you are doing, and aim for the most useful delusion in every situation you encounter. Some of the more extreme delusions (like believing that the Earth is flat) are going to be less useful than others, but if you ever need to move unnoticed among other Flat-Earthers, it may still have its place.
"Not that I am implying that I was in any personal want, for I have learned how to be content (satisfied to the point where I am not disturbed or disquieted) in whatever state I am. I know how to be abased and live humbly in straitened circumstances, and I know also how to enjoy plenty and live in abundance. I have learned in any and all circumstances the secret of facing every situation, whether well-fed or going hungry, having a sufficiency and enough to spare or going without and being in want." --Philippians 4:11-12 (Amplified Bible)
