The tendency of many is to remember the bad and easily forget the good deeds of others; there is a high probability that this is a skillful way to divert attention and thus stop the possibility of being singled out or judged. Such an attitude could almost inevitably lead to a dulling or searing of the conscience with respect to the unwanted behavior; in other words, they have no interest in being unleashed from their "hidden sins".

Another possibility is that the habit of experiencing situations with an atmosphere of evil, negativism or suspicion, forces them to consider that their environment is also cloudy.

"The thief, judges by his condition."

John 6:60-67 NKJV

60 Therefore many of His disciples, when they heard this, said, “This is a hard saying; who can understand it?”
61 When Jesus knew in Himself that His disciples complained about this, He said to them, “Does this offend you? 62 What then if you should see the Son of Man ascend where He was before? 63 It is the Spirit who gives life; the flesh profits nothing. The words that I speak to you are spirit, and they are life. 64 But there are some of you who do not believe.” For Jesus knew from the beginning who they were who did not believe, and who would betray Him. 65 And He said, “Therefore I have said to you that no one can come to Me unless it has been granted to him by My Father.”
66 From that time many of His disciples went back and walked with Him no more. 67 Then Jesus said to the twelve, “Do you also want to go away?”

Matthew 26:55-56 NKJV

55 In that hour Jesus said to the multitudes, “Have you come out, as against a robber, with swords and clubs to take Me? I sat daily with you, teaching in the temple, and you did not seize Me. 56 But all this was done that the Scriptures of the prophets might be fulfilled.” Then all the disciples forsook Him and fled.

Psalm 19:12-13 NKJV

12 Who can understand his errors?
Cleanse me from secret faults.
13 Keep back Your servant also from presumptuous sins;
Let them not have dominion over me.
Then I shall be blameless,
And I shall be innocent of great transgression.