You can be quite mistaken

You can be completely sure, or at least convinced that you are, that something is true or 'the case', and still be mistaken.

You can be totally adamant that you're right about this, and still not be right about it.

You can be convinced that what you believe is absolutely THE truth and everyone else is stupid and wrong, and still be believing something that isn't true.

You can even have insanity and be convinced that you're sane and not even suspect that you aren't.

You can trust your senses and believe what your eyes are showing you and still be mistaken about what's happening.

You can have reactions that you think are normal and natural and objective and still be totally out of touch with reality.

You can have circumstantial evidence that seems to all point toward something being true as if it's really clear convincing proof of it, and it still be a completely false conclusion.

You can think you did something or learned something already and it doesn't need to be learned and yet still fall short of knowing how to do it.

You can be sure you've fully dealt with a past hurt or a complaint or a grievance or an old hatred and have let it go and still have a shitload of release work to do (lol, story of my life).

You can be totally sure that your faculties are telling you the truth, that your mind is capable of discerning what something is or isn't, and that you are being totally objective about it, and still be subjectively hallucinating.

You can trust your ego as if you believe it is really your friend and is on your side and is helping you and protecting you and all the while being deceived and led down a dark path by it.

You can be really convinced that getting something that you're missing is going to solve your life and fix your lack and still totally feel empty and hopeless when you get it.

You can think you know what things are for or why they're happening or what the purpose is or why someone is doing something and still be totally clueless as to what the real plan is.

You can think you know what's best for other people and how they need to be fixed or helped and what their problem is and still be projecting all your own problems and unconsciousness and not even recognize it.

You can also believe you know who you are already, and think you are awake, while all the while being asleep and unaware of your real self, convinced that you are some other identity.

You might also have conviction that you really are a body or that you can die and that you're not as God created you, and still not realize that this isn't true and that you are immortal spirit.

The ego's mistakes and deceit and denials and illusions go on and on and on, always convinced of its own prowess and ability to discern the truth, or that it is actually aware of 'what is', and all the while living in a private fantasy world of insanity where nothing is true at all.

A little willingness is needed to consider that you might be mistaken or that there is more going on here than you are aware of.