There are too many keywords about the 6 colors. I won’t try to memorize the details. Instead, I will use my own keywords, which are a small subset of the original keywords. I won’t bother to capture the so-called “most important” keywords because “importance” is always personal.

• red — (gut) feelings; intuition; controlled release of emotion (“Thinking” is always somewhat controlled.)
• blue — control; unemotional; skeptical regardless positive and negative. This hat is the most ambiguous/vague, and least memorable
• black — caution; downsides/hazards; negative realism; discernment;
• yellow — positive perspective based on logic+intuition; hope; benefits
• green — creative; possibilities, unconstrained; alternatives

• White (white paper) — factual; unbiased; evidence/data/information; unemotional

— Q: why unpopular in practice?
A: Too many colors. Beside Happy/Pessimistic/Factual  I think we can remember at most one more color. Maybe ignore red/blue for now?

A: There are too many overlaps and inaccurate simplifications of each hat. Most ordinary users can only remember one simple meaning for each hat
— emotion .. In general, Emotion is always a huge distraction in any “thinking” and any problem solving. Many of the thinking hats try to contain emotion.
— which hats do I need to remind myself to wear? 1) yellow 2) blue
— which hats are too often misunderstood by me and actually matters?

black — My negative thinking is overpowering. So is XR.

yellow — hard to get right.