Most people have a strong tendency to judge themselves in a manner in which, the mistakes and errors that they make, are in the big scheme of things, from their perspective, not all that bad; especially when taken into consideration all those equivocating and mitigating circumstances as well as the big, big picture. That is to say that they aren't bad people, even though they may have done some things that could be construed as bad, but even that bad, isn't all that bad.
The problem with that sort of self-justification is first of all, it is just that, self-justification. Additionally, most people have a strong inclination to judge themselves rather leniently, whereas their judgment of others, can and often will be rather harsh, which obviously can be and is quite hypocritical. But, more than that, the very nature of dismissing one's own sins and mistakes and diminishing their impact, or minimizing them to the degree that they are now relatively small or little in their import, effectively means, that sins and mistakes, have classifications, and little sins and little mistakes are quite obviously of far less concern and impact as big sins and big mistakes.
While, to a certain degree, the above is true, it is also a deception, because most big sins and big mistakes have their very roots in the little sins and little mistakes so made, mainly because these little mistakes have not been successfully pruned away at their root, which subsequently have developed into bad habits, with bad mindsets, and bad decision making, with correspondingly these then developing into actions that are big in their negative impact and their bad influence.
Additionally, right is right, and wrong is wrong, so that little cuts made by hateful actions, selfish attitudes, and envious mindsets, to name a few, are still cuts that wound the body, and wound other people by those deeds, and are wrong for having been done. So then, though these wounds are not that deep, and perhaps are even surface wounds, they still leave their marks upon the body, not to mention that death by a thousand cuts is still death, and in some respects could be considered significantly worse than one massive body blow given all at once.
The Hippocratic Oath has been paraphrased to say: "first, do no harm," which more people need to take seriously, and to have foremost not only in their mind but in their being. Those that truly take that to their heart will recognize that retaliation, meanness, inconsideration, and other negative traits don't need to be followed through or actuated, because they are harmful for the person so expressing such, and for those that receive such, in virtually all situations. So then, in our lives, what we say and what we do matters, and the things that are in our control are our responsibility, and to belittle our mistakes, errors and sins as being of little consequence, because they appear to be relatively minor, is the reason each one of us is not the person that we really could and should be.