I have anxiety issues and in situations where I'm unsure I tend to become observant too, and at times quieter than I would like. It's self protection.

I can be judgemental too, but as I've got older life has taught me that I'm not always right in my first impressions. Sometimes when I get to know someone better over time it turns out there is far more to them than meets the eye (in a good way) and I change my opinion about them. Other times there have people I instantly take to (they tend to have charisma) who then show other sides of their personality which are not as nice.