^ Not to me, but to the server the GI's (I presume) were ordering from.
Basically, dudes were ordering in English, Japanese girl taking orders seemed a bit flustered and didn't understand and asked them to repeat the order. One foreigner asshole gets agitated, raises his voice and orders again like a dick. 'NO KETCHUP, OK?! DO YOU UNDERSTAND? DO YOU NEED ME TO SAY IT AGAIN?!" His posse laughs, and asks his friends why he can't get any good service "around here". I honestly felt bad for the girl as she was on the verge of tears...
Obviously ruined the night of the entire staff working there and made my burger less delicious but still delicious nonetheless
During my living here in Japan, the majority of foreigners have been cool and easy to get along with. Okinawa was the only place I saw any of that douchebaggery going on.