Proverbs 28:26 He that trusteth in his own heart is a fool: but whoso walketh wisely, he shall be delivered.
Somewhere along the line, many have chosen to believe "trusting in themselves" is a sign of wisdom.
I think it is easier to take this stance when you have completely disregarded YHWH as a factor in your life, or compartmentalised Him to the point where He only exists when it suits you.
If you don't believe in YHWH, or don't believe there is a Elohim, who better to trust than yourself? Can you really trust anyone more than you trust yourself? Yet this verse calls the person who trusts his own heart a "fool."
If trusting in my own heart is foolishness, then where does wisdom come from? Apart from the influence of Ha MASHAYACH, our hearts are desperately lost and confused.
After all, who designed your heart? Who knows you completely, and is able to author wisdom for your life?
“All your children shall be taught by the Lord, and great shall be the peace of your children.” (Isaiah 54:13), 'Peace'