Lonely people with drinks sitting and staring in to the wall hoping that someone will talk to them although they have forgotten how to show signs that you are willing to talk to someone. So they look like they will kill you if you talk, but if you do still, you'll have to listen to them for a week.
I strook up conversations with them all the time, tried to get them to talk to each other. Like "Hey, Rick over there has a motorhead t-shirt!" Like some kindergarten leader.
Daytime bartenderns should get some pedagogue education.