They can force you to test your beliefs within that reality and when they fail, they can say your beliefs are incorrect and therefore your reality is not real.

For instance in your reality you can fly, i challenge you to jump off the top of my car and take off....when you land on your ass and break it i can say you were not living in reality and you cannot fly :-)

our indivdual reality is the equilibrium point between the extremes of our experience.

What they mean when they say you are not living in reality is really "your experiences do not match mine". and what they tell me is they are so intrinsically superior about the quality of their experience that they cannot value the what they decry - it could be superior. Nor can they concieve of the possibilty that thier own actions might fall short of thier self-image or concede that may be true of another - and that's why thier superiority is not well recieved.

now have i got "my head in the clouds" as my reality is often defined by others or do i have capacity provided me by my differing experience that another's lack of coorealation of experience does not allow them to value?

if they persist in failing to understand what you understand remind them your understandings don't require them to

There are no multiple realities, there are no multiple nows. In the moment two people can see the same thing or not, but that is not because there are different realities it is because the two people are either seeing different aspects of the one reality or are interpreting reality differently or are in fact imagining different things. The last two, I am assuming are what you call fiction.

Two people can experience reality differently but that is not because reality is different it is because their being is different, just like different size cups will hold different amounts, so are people in regards to their ability to experience the moment.

So it is not that everyone's reality is different it is everyone's ability to experience reality that is different. Therefore if someone shares some aspect of reality that they are aware of that we are not and we accept it, that is become aware of it too, then our sense of reality grows, in other words, our ability to experience reality or 'now' grows.

But if someone is not very good at experiencing reality, they will rely more on their imagination, opinions, past belief structure and subjective reactions to reality. This is obvious to anyone who makes an effort to be present to the world around them in the moment. The line you draw is you.

Every subjective test seems to prove that we have the capability of experiencing 99% of reality in like ways. If I say that an orange is round, and ask you what other items are round, you will answer "balloon, apple, golf ball, the world", etc. We comprehend the same aspect of reality in the same way, even though we have different viewpoints and different brains. This seems to apply to all physical manifestations of reality.

In so many words, someone else's definition of fiction versus reality is likely to be very much the same as yours. No one 'knows' that there is a supernatural aspect to existance. We might have some anecdotal evidence of that, but scientific recreation of supernatural events doesn't seem to me to be a possibility.

For abstract manifestations, say "happiness", or "fright"...apart from the physical features of such feelings, it is harder to determine whether we 'feel' things the same way, but you really can't show any proof that we 'feel' things differently, all else being equal.

Mind altering drugs, psychoactive substances, alter your overall perception so that you believe you see things that your companion, not imbibing, does not. Just a chemical reaction in your brain.