could you see how seeking "truth" might be more important than being happy?
I suspect that human nature is largely built on aggression, and that even when people "act nice", that they do so on a foundation of aggression.
how do you factor in that stereotyping, classifying, and recognizing patterns in large groups has merit too? How else would you practically apply group observation on a personal level in real life?
Here you talked about "large groups". Sure, there are large groups of people that are more or less aggressive, selfish and superficial, you are right. Then there are groups of people that are selfish and superficial, but not aggressive. Also, groups of altruistic and genuine people. And groups of people who are more neutral there...
Recognizing patterns is what I constantly do. They can become rules, but in the end, they are always based on statistics and hypotheses. They can help me to understand the big picture, but every individual is unique and applying the same principles for all doesn't seem very wise to me and I've always allowed myself to see beyond a simple rule/stereotype in people. The same way, I see classifying as a help for me to understand the big picture, but the details are what matters in the end.