Funny story. I was once in a British pub with some American friends. We were in a booth by the front windows and two of us needed a refill. I looked towards the bar, trying to get the bar tender’s attention, as it was crowded and loud in there.
I finally get him to see me and I throw him a hand signal with two fingers held up, so he can see that we need two refills. Next thing I know, the guy’s face turns angry and he moves to jump over the bar towards me.
Just then, the owner grabs him by the shirt tail and stops him. They have a couple of words and the bar tender calms right down.
When the owner brings our drinks he explains to me that holding up two fingers with the knuckles facing outward, is the British hand sign for FU.
Germans also mark each glass with a line indicating the proper level for the glass being full. One early evening, two co-workers and I were the only customers in a German bar. We each ordered a local beer from the only barmaid there. A few minutes later we still hadn't been served and noticed the barmaid was sitting in the corner reading a book. It took what seemed like another ten minutes before she finally delivered the beers. After finishing them, we ordered refills. Again, for the first dozen minutes, or so, she sat in the same place reading her book. We finally found out that the beers we ordered were prone to a large head. In order to meet the law, the barmaid had to top them off several times in order for the liquid level to reach the 'full' line, and, of course, had to wait between the fills.