I had a similar moment of confusion when I realized "normal" people have to put forth effort to think. Your brains aren't always on, always thinking, about everything? You don't always notice every little detail (though sometimes at the expense of the bigger picture)? How can you do one thing over and over again without getting bored? You just obey and believe things you're told? You can follow rules you don't personally understand a need for? You've been doing a thing the same way forever just because that's the way it's always been done?
Sometimes it's aggravating to me as it seems like other people are being intentionally obtuse, but other times I envy the ability to float through life, free of thoughts and therefore free of anxiety.