First of all we need to understand that reality is both shared and subjective/individual at the same time. 

The thing that makes a shared reality personal, is the filter we use through which we perceive the world. This filter determines how we see things, what we pick up from the world,  what we ignore from it, and according to those things how our life story evolves. 

The filter is influencing everything.  Imagine it like a pair of glasses. If the glass is clear and clean, you see the world colorful, what you see, you see clearly and sharp. You still need to turn your head toward things so your eyes can see them. The filter also influences how and towards what direction you turn your attention. The glass can also be (and often is) dirty, blurred or tinted.  For example if the glass is red, you see the colors differently. You stop seeing red things altogether, they get filtered out. Green becomes brownish, blue becomes purplish yellow becomes orange. The same way an emotion filters and makes you see reality differently. When you are in love your reality seems different from when you are depressed. This filtered reality isn´t shared, it is personal, depending on your momentaneal emotional state, your spiritual and psychical development, your physical and/or mental state.

This filter determines your affinity with certain things in the world, and that affinity defines the path your story evolves on. The comparison with the tinted glasses isn´t just an example, in the sense of our energy it is also very literal. If our chakras are neglected, clogged up or blocked, that directly influences our filters of reality. 

Like when something catches your interest and suddenly you see those things everywhere. For example many women who start to think about having children, suddenly start to see pregnant women all over the place, they seem to appear whereas until then their presence was never as notable. Or certain numbers that keep appearing, or motives, patterns. It´s all there in front of us all the time, we just don't pay attention to them until it becomes a personal interest for some reason. 

This is also how tarot works. The cards “come to us” because that is how we filter our reality. Since the cards have their own energy, we have more affinity with certain cards than with others because that s how our reality is shaped. That which we have no affinity with whatsoever - we completely ignore. 

Our shared reality is way richer than our personal reality, it contains many details we never even realize or see. The more conscious someone is, the more aware they are of the filters and the ways to keep them as clean as possible, the richer and wider the world becomes to them. 

It is also useful to be aware of this before we pass judgements over certain situations, people or things.  It is useful to remember that people might see things differently because they wear different filters. Moreover, some are almost completely blind to anything else but their own filter, living in the profound belief that theirs is the only possible reality there is. Some worlds of some people are really tight and tiny. We need to know this to be compassionate with others. Also it´s handy to keep us from obsessing too much over things. Seeing the world through a determined fear can make us paranoid about everything. That is how fear can overpower us.  We fear of one thing, reflected and seen  through everything. A whole reality can be reshaped by one single fear. 

To each of us, our reality is personal, and it is wise if we don´t confuse it with our shared reality. No one, truly lives in the shared reality, everyone lives in a slightly different, slightly tinted, slightly bent one, some ignore the things you see the most clearly, some see things that are not even there from your point of view. It´s not a good thing, or a bad thing, it is simply how things are. These filters change sometimes, people can be helped to clear them, and their world will seem to change, their perception will be different too.  People whose filters are similar to ours, will feel closer to us, we say “we have a lot in common”, our realities are closer.  

Sometimes bent, tinted and distorted realities can seem to be shared ones, it´s how sects and psychosis work. The point here is to make people adapt a certain filter of reality and make them think it´s THE only one. This is achieved by having common fears, a common enemy image, common values, common judgement. Many oppressive systems work like that.  They usually come with a pre set value system, defining good and evil, setting up a moral code that is usually in some way self serving and oppressive. To establish this they have to “sell” their own filter as “the norm” or “normal”, so anyone with a different filters becomes abnormal. This of course is artificial and as such, very intrusive for everyone involved.

So the source of reality isn´t really the world, it is our filter and our mind. That doesn't mean the world doesn't exist of course, it only means that there is much much more in the world than what there is in our reality, and that is fine that way. 

There are people who suggest we can create our own reality at will, and that is another thing I don´t necessarily subscribe to. We co-create our reality. We co-shape it with our actions, with our decision and choices. All of us, together. I don´t believe in wishful thinking either, nor in positivity to attract positive things. I see people fooling themselves, thinking they can lie themselves happy or rich. I see “the law of attraction” as a scam too, because juggling with half truths it is passing over value systems and for more convenience implies what you “should” wish for in order to be “happy”  I think there is way more to that. Not everything we want serves our progress. Not everything we wish for is worth the price we eventually have to pay to get it. Whoever tells you, you can just ask things from the universe and you will get it, that you can just take and take for yourself, no questions asked - is a trickster. What you want is not necessarily the point, and more often than not it is not what you need either.  People used to have more sense of balance in the older days when they would always offer something to the Gods before they would ask for something for themselves. 

I see the attitude that is spread by books like “The Secret” as dangerous and harmful.

I don't think we attract things into our lives, I believe we turn our attention toward things more when we observe the world through certain filters. It is true, that when we walk on our path of progress the universe seems to align with our actions organically, but that is not because we attract those things, but because on our path of progress we are in harmony with the Universe. It is our path of least resistance and that is the natural state of the universe. Our harmony shifts other people into theirs and it makes us work together. That is how and why the universe aligns, not because somebody WANTS something very much. It´s similar, but its not the same. Sometimes somebody wants something very much because that is their path. But that something is rarely money, a house or a car. It´s more to create or to discover something. In other words it´s something that adds to the world, rather than taking away from it. That isn´t to say, that wishes don´t come true if persued, they do, but sometimes they come with a very high pricetag. And eventhough wishes do come true, one can´t build an entire reality based on their wishes. Simply because the shared reality is co-created. If I wish for something, and somebody else wishes for the very same thing, one of us will have to live without that wish coming true. So the wishful-reality idea induces a competition, instead of sharing attitude. It creates a demand rather than greatfulness and it is a major filter that makes us ignore everything else until we get what we want. It directs peoples attention to their Egos in terms of what they want to own.

Shared reality is everything there is. Discovered and undiscovered, written and unwritten, sung and unsung. 

Our possibilities within that are however determined by time, space and a set of circumstances. These are things we cannot change and what we part from. 

Everything else concerning our subjective reality is shaped through and by our filters, and with those we have quite a bit of flexibility if we become aware of it. We can choose to adapt or not adapt a certain filter that is offered to us by others. We can aid ourselves with filters that are better fit to our (real) needs. We can try out other filters just to see the same situation with a different perspective - which is basically what empathy is all about. We can show others their situation with different filters too, so they can understand it better, or so they can evolve their empathy as well.  

The more flexibility we have with our filters, the easier it becomes to deal with life´s challenges. It doesn't mean we can avoid hardship, but we gain flexibility and strength to  face and overcome whatever life throws our way.