1. Emotions thoughts and feelings can hurt you if they were not researched.
But sometimes in doing research we often use emotions and feelings for example when we are going to invest in a new coin we will not know that the coin will be in good development until a certain period of time and when choosing it only feel that the coin will be good even though reading the whitepaper too or the roadmap won't really know it.
4. Diversification that has no research behind it is foolish.
In crypto even if you do research first by diversifying it is still a stupid act, you will be safer by holding only one coin, namely bitcoin than dividing it into altcoins