Our brain doesn't bother to understand most of the time, it just looks. Someone can change a variable right under our nose and we won't notice the difference.
The broader implication of this is that the more we choose to focus on one thing over another (i.e. social life over satsang), the less likely we are to be attentive to the other, notice its intricacies, and appreciate it for what it is. Satsang just becomes a part of the background image -- the part that we conveniently don't really pay attention to even though we think we are (e.g. there is a difference between doing puja and focusing on puja).
In short, our brains are wired to do only so much at once; take a look at this Youtube video.