@WombatChocolate
Although, I am a Christian, I have suffered with low self-esteem for a lot of my adult life. Whilst, I believe God loves me and cares despite my flaws & faults; He/she is not the problem - I am! but that's okay, because I am human
As I said earlier, it has taken years to work on my self-esteem (with help), and although I am capable & confident in some areas of my life, in others, I am not so much - and still have wobbles - & that is okay.
Everyone and their lives are different, and what is easy for some, is harder/tougher for others.
Our inner pysche is affected by so many things as we grow up, and as we grow as adults, we understand more, and see others looking as if their lives is so easy & we hurt and question our own abilities to cope with life. But many are wearing an outer mask, just like the rest of us.
Those with low self-esteem exist in loving families, may have lovely friends etc. etc. But, low self-esteem is vicious, undermining, internal and it doesn't let go easy.
People with it, are not weak, they struggle their way through an internal noisy jungle, surviving their everyday lives in spite of the added emotional stress and chaos of life. They are resilient and 'stronger than they think' - and while I don't particularly like the word 'strong' - we bounce back or drag ourselves us somehow and carry on.
Hope this helps, people understand better
Otherwise, agree with what good self-esteem is, as described by other poster and your good self.
Peace and love