They became rigid and overconfident in their knowledge, scattering their wisdom and ultimately retaining only a tasteless, basic essence.

This couplet speaks about a common human tendency. It suggests that when we become 'thick' or arrogant with what we 'know', we often dilute our true wisdom. Instead of gaining deeper insight, we end up in a muddled or confused state, like a messy porridge. It's a reminder that mere knowledge can make us conceited, but true wisdom requires humility and prevents us from losing our clear understanding. Don't let your knowing become a hindrance to true wisdom.