When someone lives a lie, it does not match with any sign of the truth
One thing is to have all kinds of desires to which we can determine as our set of dreams, but another thing is to try to live under a self-deception, that only hurts the person who does it and no one else, it may be that for a certain time can get to deceive others but it will not be for long, or will not be forever, I have always considered very important to have defined the necessary line between the real and unreal, that is the most important reference for everyone.
Each person according to his capacities will know his possibilities of success, and in this way he will measure himself both internally and externally, he will test himself with each of his actions and so on until forging his true expectations of life which if he knows how to use them he will walk on the path of his own well-being and that of his own, only when he manages to measure what his capacities are he will be able to move away from the self-deception trap towards himself.
When someone fails to calibrate its internal capabilities can not know what is done and how far you can get, and may even be tempted to want to live a world of illusions where the most damaged will be the same, you can notice this when you say something to someone that is the truth or is close to it and refuses to even analyze for a moment, we realize that hardly compagine with what we are saying.
If someone you appreciate or value very much tries to live on illusions, the best you can do is to let that same person break his own bubble of deception, otherwise he will always refuse to understand that he is self-deceived, and if we insist a lot to let him know, then, it is possible that he will become even more enclosed in his own deception, from there can only come out that person who wants to and does it by his own will.