It’s good to stay focused on what’s in front of you.
The job at hand, the person you’re talking to, whatever ....
... because over time, it makes you a more efficient and useful human being.
I knew a person at the studio I worked for who spent most of his time watching the little television on his desk. Work was kind of an after-thought. The supervisor let him get away with this behavior (I guess it was the era) but others in the department resented it, and it made morale kind of crappy.
And while a business representative, I dealt with an official from another guild who, when speaking to you, never gave eye contact. During almost every back-and-forth, he would look over your shoulder, scouting for more important people in the room. (Sadly, there usually were more important people in the room.)
This was irritating.
Basic rule: If you pay no attention when engaged in one-on-one conversations, at least master the art of pretending to listen.
(* The first of a now-and-again series.)