At the timeframe I visit the store it is usually empty. I usually sit/eat/go. As I received the call I kind of panicked as I had my food untouched and I really wanted to elicit this gentlemans assistance with a project I am currently working on.
Everything was going perfectly and the usual staff greeting did not interfere.
I was in a Dunkin Donuts a couple of days ago and had a similar situation come up. The place was empty when I arrived so I thought it would be a good place to take a conf call. Well, sure enough, as soon as the call started a customer comes in with her two kids. And sure enough, they messed up her order or were taking too long and she was acting like they had called her baby ugly. She made a huge scene and I was trying hard to keep my phone on mute between blurbs. I got so annoyed that I almost yelled at her and the staff before I realized that I should probably just leave and finish the call in the car, which is exactly what I did.