The hyper-specialist shops of Berlin
Several hyper-specialist shops I know in Munich:- balloon shops seem to do really well because we have several here and every major city seems to have one- foam shop for when you need to fix your upholstery- venetian blind store which only sells the vertical kind- Ketten Wild was a chain shop that only sold chains but chains in all forms and sizes- la porcelaine blanche's slogan is "only china, only white" and that is what they do- elk shop for everything elk related - not that we have any elks in Germany but elks are cute- Schrauben Preisinger sells only screws. They claim they have 30000 different types in their store and this is absolutely credible. A few years ago I was there to get some M1 screws for a project when I witnessed an interesting exchange between another customer and a salesman. The customer had brought a screw with a quite wide thread. It was a straight screw, not tapered and not a wood screw, just with an obviously non-metric thread. He inquired if they had this type of screw in stock. The salesman answered slightly offended that this was a shop for machine screws and they would not sell furniture screws.Also button shops are super useful. If you lose a button you go there with your piece of clothing and they will find a suitable replacement in no time. I never visited the one in Berlin but the one in Munich saved me good money.EDIT: I just remembered two more:- Gummi bear shops are a bit like balloon shops. I don't understand it but there seems to be enough demand to support several of them in a single city.- Berlin's Ampelmann. Maybe doesn't quite fit into the category because it's more of a tourist curiosity. On the other hand: A shop that only sells stuff related to the graphic design of a symbol on the traffic lights of a defunct state is quite hyper-specialized I guess.