You attack my surety but the passive-aggressive tone of your comment gives me good reason to suspect that you are also quite sure of your stance. I would also wager you would be less likely to change your position when offered new and compelling evidence than I, but that is neither here nor there.
Reality is just that: reality. It's not one's perception of reality, it's what is. Reality is also consistent, within it's own rules.
We have ample evidence that cognition is created in the brain. We have ample evidence that our thoughts are the product of neuronal activity within our brains, and we are just really beginning to understand the mechanisms behind our quite amazing brain. There are many studies detailing experiments that have induced a wide range of feels in human brain using only physical means, including inducing the feeling of a spiritual experience.
We have ample evidence that chemicals, and brain structure affect that way we feel and what we like, love, hate and fear and that these are affect not just by our life's experiences but the millions of years of our evolutionary heritage via genetics. Saying that science is useless in understanding human thought and motivation is much like saying that physics is completely worthless because it has not identified and categories every snowflake that has ever been. You don't need the structure of of every snowflake to understand what conditions create them nor to predict when they may fall, and you don't need to know everything about every thought to understand why people have thoughts and to understand the general principles behind their existence.
Why it's true that our only window to reality is via our own consciousness and thus coloured by our own internal reality (which is not reality but our perception of it), we have found a system which can break through the fog of our minds and allow us to understand what reality(actual reality) is. This system is called science, and there has been no other system that even comes close to it's effectiveness at determining the truth.
Coming back around to the topics you raised, "love, justice, forgiveness, mercy, compassion, gratitude, contentment, etc", I will admit that science had has little to say about these concepts. That is because there is no one right answer for these things. They are non-deterministic, relative to the cultural and value system of the system the individual resides in and also the conditions in which such a culture exists. I will point out that the non-science based systems also fails us in regards to these topics, with little poking around one can find all sorts of different answers in regards to the above topics. Even looking at some other metric than consensus, non-science based methods to approach the above topics seem to do as much harm as good as the world is full of people who think they see the truth and insist that others see it the same way.
At least if we can understand why people feel the things they do, and the physical fundamentals behind them, we should be able to make more informed decisions and create more rational belief systems. Mysticism can not do this, science can. And perhaps one day will shed the vestiges of our collective evolutionary physiological heritage that served us well when we huddled in caves when danger and mystery did indeed surround everyday existence, but serve us much less in the modern. Surely one day it will be a positive step for us to look up at the starry night sky and not see outlines of mythological beings but the next stepping stone for humanity.