T - E - R - I - Y - A - K - I spells teriyaki. It does not spell coffee shop or cafe or Starbucks. So why would you walk in and order 2 lattes, iced. And then when the Asian guy looks at you blankly, don't speak more slowly in case the language was a barrier. Because the teriyaki restaurant does not have lattes. They have teriyaki. Hence the name. Then, once it dawns on you that you are in the wrong place, and you think about ordering food, you should at least have the courtesy to wait until the guy is free before you start shouting an order to him. Then don't storm out in a huff because he isn't dropping what he is doing and he can't help you right that second. I don't think decent behavior is too much to ask for.
Fellow teriyaki diner.