Why is it that things that are meant to be substitutes for the real stuff are considered “the default” in the Czech Republic?

     I’m at a party and the hostess comes out of the kitchen to take orders for coffee. The question each guest is faced with is “normální, nebo zrnkovou?” where normální refers to instant coffee from a plastic jar and zrnková means coffee made from ground coffee beans. Everyone asks for normální and I feel strange.
     When it’s my turn to be the hostess, I buy fresh Brazilian coffee beans and make sure there’s enough cream and sugar for everybody. When the time comes to serve coffee and the guests find out there’s no instant coffee in the house, one of them opts for tea instead. (As a side note, I was visiting with friends once and was served normální coffee creamer, which came in the form of a white powder.)
     I was in a grocery store with a couple of Czech friends. They wanted to help get stuff, so they asked what all I needed. I said I needed butter.
     “You mean margarine?”
     A minute later they noticed me looking around helplessly, so they inquired what I was looking for. I said I was looking for milk.
     “Why, it’s right here!” and they pointed to the boxes of trvanlivé mléko, a nearly non-perishable, strangely tasting white liquid with an expiration date several months in the future. I specified that I was looking for normal milk. They didn’t understand and I quickly realized my mistake. The perception of what is normal can be very subjective. So I explained that I was looking for fresh milk. There was none to be found in the store and again, I felt strange.
     I have been called a beer snob by my American friends who drink nothing but Bud Light. I have been called a coffee snob after I fell in love with Hawaiian Kona coffee and wouldn’t want to drink any other kind for a year. I must be perceived as a tea snob since I buy specialty loose teas, store them in airtight tin cans and brew them through a cotton filter. Now I can safely add two more categories to the list. I’m also a butter snob and a milk snob.