The above quotation comes from Victor Hugo's seminal work, Les Miserables, and such should be taken to heart by each and every one of us. So too, we read in Holy Scripture, this short passage, "Jesus wept." (John 11: 35)
While this world and the people amongst it, can provide us with times of happiness and joy, it has never been and never will be, nothing but happiness and joy, for there is far too much pain and sorrow that exists throughout society. So then, all those that try to live only within a construct, in which, they ignore the suffering and pain of mankind, or pretend it doesn’t exist, are the very people that clearly do not see.
To not weep in this world, signifies a personage that does not see the world for what it really is. Further to the point, the tears that each of us should shed, while representing many different things at many different times, primarily should be about what is the most obvious thing to see, which is mankind's continuous inhumanity to mankind. That is to say, there isn't any reason why there has to be wars, or fights, or famine, or any of the other negative things that occur, day-by-day, but these very things, no matter the great prophets and messiahs that have lived alongside us, or the holy books so written, are part and parcel of everyday life, though it need not be that way.
This signifies fundamentally that a huge swath of mankind refuses to learn the most elemental lessons of how to conduct their lives; for those that are unable to see their neighbor as their own self, are truly blind and do not see. So that, the very first step in correcting wrong behavior is quite obviously to recognize that particular behavior as being wrong, and the second step, which is never going to be easy, is to thereby correct that behavior on a consistent basis so as to fundamentally improve oneself for the benefit of all.
For some of us, that do see, we weep, not just for others, but for our own self, for we know that we have failed to live up to what we could be, and further that we have failed to do the very things that we should be doing. This doesn't mean that we should stop trying or that we should simply give up, but rather through our own diligence as well as through the help of other good people that care, we must try and try again, for anything of real value, necessitates a consistent and dedicated determination to achieve it.
There are also many different ways to weep, besides just the tears that come forth from our eyes, such as through the abuse of drugs, or through the abuse of alcohol, or through the abuse of others, or through the abuse of our own self; for each of these fundamentally is an acknowledgment that not all is right, in ourselves and in this world, and thereby we weep and will continue to weep, until such a time as we recognize that what we see can actually be changed, and that change begins first with our own self, straightened out, and willing to do what needs to be done, no matter the cost and carried out for as long as it takes, until even, the end of time.