Have you ever used a map or GPS to find a place? If you pay attention to it, you get there just right. But if you think you already know the way and don't check anything, you risk getting badly lost.
The Bible says a wise person understands their own way, but the fool goes on deceiving themselves. The fool thinks they're doing well, even while lost, because they don't want to admit they went the wrong way.
Think of a friend who always says "I didn't do anything wrong," even when everyone saw them mess up. They're deceiving themselves, and that only makes things worse. Whoever has the courage to look at themselves and admit "I messed up here" can correct course much faster.
Jesus said He is the Way. When we really follow Him, honest about who we are, we stop deceiving ourselves and start walking the right path, without fear of admitting mistakes along the way.
Whoever deceives themselves gets lost. Whoever knows themselves finds their way.