It Is called the Problem of Evil, that the existence of evil - something we can all see and are familiar with - makes the existence of God impossible, or at least extremely unlikely.
A lot of very heavy thinking has been put into this, certainly, by philosophers attempting to define terms and see contingencies and answers. I don't want to claim that all people who cite the problem of evil are intellectually and morally lazy.
Yet most people who fall back on this argument against the existence of God are simply being intellectually and/or morally lazy. It amounts to nothing more than a feeling, or a fifth-grader's first thoughts about the world and how it works that goes no further than posing the difficult question and pretending there is no answer. It is not really even a question, but an evasion of questions. I have mentioned before that I consider self-deception to be the one great obstacle to belief in God.
The problem of good is more difficult, and more profound. If good exists, that is at least a mystical proof of the existence of God, though it is legitimately unsatisfying as an intellectual proof. Yet that problem is addressed far less often. It generally does not occur to those who consider the mere reference to the problem of evil as a disproof of God that there even is a counter-question.
Seeing that good does obviously exist...