People who are ignorant about beer tend to annoy me to no end, especially when they are bartenders. Two examples:
There's a local pub I'll stop in to have dinner and a beer on my way home from work. This particular pub has a beer list that they think is something to brag about. There are about 80 beers on the list, most of which are all the varients of BMC and then there's your foreign BMC equivelants like Molson and Lowenbrau. The remainder , which is probably 10 beers are usually never in stock. Out of these, the Hacker Pschorr Weisse beer is usually available; so that is my logical choice. Well, one day I order my Hacker Pschorr and then the waitress comes back to tell me that they are out of the Hacker Pschorr; but they have the Paulaner in stock. Hey, I like Paulaner Weisse as well; so I'll go with that. Next thing I know, she's bringing me a bottle of Paulaner Marzen. I politely explain to her that it's not the same type of beer and she relays the message to the bartender. In turn, he gives her hell and tells her that I don't know what I am talking about. Needless to say, I stopped going there after that.
The second incident was at a different bar, and again, I order a weisse beer. After taking four years of German in high school, I pronounced it "Vi-seh". The bartender looks at me puzzled and I repeated myself a second time and then a third time. Now the bartender looks at me and says, "Oh! You mean "weeeeeesss" beer!". I think I was ready to slap him after that.