In hindsight yeah it's obvious. But at the time I had a mentality of "well you can't know for sure, you can't assume this signal means that, it's not scientific, it's not objective, etc." There's also a part of it that feels kind of judgemental and impolite "intruding" in that way, especially if you make the wrong read.
No not exactly, it was more "I'm not arrogant enough to assume I know someone better than they know themselves, I'm not going to dogmatically explain a person to themselves as if I have all the information and can magically intuit and deduce everything about them." This is still generally true, not just for myself, but for every rare true student of human nature there are a dozen fools trying to make a read and failing miserably.