I honestly feel indifferent about giving my opinion because I have never actually ate at a place by myself... Maybe sat there while whoever I was with walked somewhere like the restroom and I can't say I feel uncomfortable or anything but I don't love it persay. But without me truly having done it by myself how can I really honestly say if I am comfortable with it or not.
I have no problem with it. I have had to travel on my own a lot and have a spouse who has been deployed. Being alone wouldn't deter me from having a good meal. To be honest, sometimes I really enjoy it.