Haanel says right in the beginning of the MKS, that the LoA is not bringing to us what we desire or what we think we deserve or what someone else has, but it brings us "our own". How so?
The answer to this is easy: we have nervous system which receives the signals from the outside, passes them on to our brain, which then interprets them according to who we are. Read: our internal programming, effected through our upbringing, our education, belief system, etc. is what then translates those signals into emotions/feelings and thoughts. But these aren't fixed. We're just looking at them through our lens, that's all.
Example: if someone uninitiated looks at a fire-walker (walking over hot coals), he will probably break out in angst and sweat, because his belief is that you will burn yourself. Put that in contrast to someone who has fire-walked before and knows from experience that it won't hurt you - he'll be literally left 'cool'.
So you see there is no such thing as an overall reality, only individual realities. And if you don't like your interpretation of reality, change your thinking. Make that counter suggestion as mentioned in Part 2, make it over and over again. What happens physically is that you develop a different sensitivity, so you will not only pick up signals of a different nature, but you will also interpret them differently, thus creating a completely new reality for you.
So the Law of Attraction then brings to you your "new Own", because through repetition you've formed new habits and made certain processes subconscious. "The word became flesh." And now, with you being "different" to how/who you were before, your interpretation of the signals from the outside is an entirely different one. So what you now pay attention to, you become conscious of, and this is health, wealth and happiness. Simply because you've dared to look in a different direction and were exposed to different energies. This way you can turn everything around that you desire to turn around, and you see that there is no magic or occult stuff involved, just Natural Laws.
Haanel made a point of the MKS being scientific and not some make-believe stuff, and this proves again that he is right, because if you focus your attention on all that is pro-life, or life-affirming, it will show more and more in your own life, until one day it's as normal as it can be, because it's automatic, sub-conscious and therefore removed from your conscious interpretation through your mental faculties.