The biggest illusion dictating our lives is Expectations. We expect life to follow a certain path: that was good enough for my grandfather and it's good enough for me.
In all aspects of our lives, we have expectations. my children should be a certain way, my partner is supposed to be like something, my job is supposed to fulfill me, my house, my dog, my life.... Everything is supposed to fit into my expectations. And does it?
Almost never. But that doesn't stop us. If once in 100 times, an expectation is fulfilled, we take that as being the norm and all the 99 other times where our expectations weren't fulfilled, we pretend they are the exceptions.
Why do we do that? What's wrong with the not knowing what's coming? Well we like stability and will do almost anything to avoid change. Including deluding ourselves that our expectations are somehow justified, in spite of all the evidence to the contrary.
Together with false expectations are the endless comparisons: You should be more like so and so; why don't you behave like so and so; etc.
So whatever you do, it's not OK to be you. Couple that with the endless expectations which others dump on you. it's no wonder that we end up pretty crazy. There's an article in my head all about the teenage years and the effects of unreasonable expectations placed on our children and their effects.
So, if you want to escape the illusions, then the first thing to get rid of are the expectations. Acceptance is the key word.