Yay or nay?

Background for why it's on my brain: I have a regular customer who comes into my store and browses for upwards of an hour, all the while singing and whistling loudly along with the music playing (which, for us, is the same 8 hour soundtrack that we listen to every single day of our lives at that store). Some of my coworkers don't mind her, some want to strangle her.

There is also a cashier at the grocery store by my house who sings his entire interaction with you, with greatly exaggerated vibrato and inflections. Some people adore being checked out by him, and some people will stand in line for a half an hour to avoid it.

What say you, GT? Are public singers endearing, or are they nuisances who must be stamped out?