What is the significance of the title " A Good Man is Hard to Find"?

The family stops at Red Sammy's to eat. June Star comments that
is is a broken down shack. The grandmother, who is selfish herself, notes that things aren't like
they used to be and she tells Sammy he is a good man for letting two boys charge some gas.
Sammy's wife brings the food out and adds that you can't trust anyone. Then they talk about the
escaped murderer, the Misfit. The consensus of this conversation is that no one can be trusted
and the the world has become a more violent place. The children are not respectful but really
every character, with the exception of Sammy perhaps, is only interested in selfish
needs.

After killing the grandmother, the Misfit says she may have
been a good woman if someone had been there to shoot her every day of her life. What he means is
that the world is so off balance that it takes these extreme situations to prompt people into
behaving unselfishly. If everyone is selfish and untrustworthy, maybe the only thing that would
make them appreciate life and others would be to constantly face death. It has been a subject of
debate whether or not the grandmother actually achieves grace when she says the Misfit is "one of
her children" or if this was also a last ditch effort to save her own life. This ambiguity shows
that a good woman is also hard to find. In fact, it is interesting to consider if O'Connor may
have intended this ambiguity.