OK, so Swedes hate standing in line. Which I totally understand. But since it is impossible to get rid of lines all together, and still get anything done, they have found away around this. They instead insist you take a number and wait until your number is called.
They do this everywhere. At the bakery, at the bank, at the train station, at Cervera to buy Royal Copenhagen stuff, at the cheese shop. You take your little number and wait. This can often be a useful solution. If the weather is nice and the sign is big enough, you can wait outside until your number is called. Or you can browse around, until it is your turn.
The trouble is when you don't realize the store has a number system. You wait and push your way up to the counter. That is when the sales person refuses to speak with you, and just points to the number sign on the wall. Then you have to search frantically for the number dispensing machine, which can be hard to find.
Occasionally there is solidarity in numbers. Someone decides they don't need their number, so they pass it on instead of throwing it away. Someone accidently takes two numbers, and passes one on to the next shopper. It is one of the few times I have seen Swedes who don't have to interact with each other, volunteer to interact with each other.
It used to be that Systembolaget – the Swedish socialist alcohol monopoly – used the number system to dispense all of the alcohol in the country. It was quite a way to spend a Friday evening. They kept all of the booze behind the counter. You filled in a little slip with your order, and they picked the alcohol for you from their warehouse. These days the Systembolaget is still a socialist alcohol monopoly, but they have instead filled their stores with good old fashioned capitalist shelves. They allow you to pick your booze yourself, in the glory of flourescent watt lighting, and wait in a regular line to purchase it.
Before heading to the counter, check for ticket dispensing machines and a screen displaying numbers.