In the beginning of Psalm 36, David gives the key insight . . . the one thing . . . that keeps people from God. Pride, and more specifically, pride in their own self righteousness. The wicked flatter themselves and cannot detect their own sin.
This is true of all of us. As David points out again in Psalm 19:12-13 and Psalm 51:10-12, we are not even capable of recognizing our own sin without the assistance of the Holy Spirit. This is a continuing refrain in Psalm 139:23-24 and 1 Corinthians 4:4-5.
It was this self righteous pride that caused Pharisee to miss their Messiah (Luke 7:30) because they couldn't repent, acknowledging their sinfulnes and turn to God (Matthew 3:1-11)
That is still the biggest hurdle people have coming to Jesus today . . . acknowledging their own sinfulness, that they can't do it on their own, and need a Savior.
https://raisedtowalk.org/r36
More on Reading through the Psalms
https://raisedtowalk.org/psalms
Passages from the World Messianic Bible