Yes, the German and Belgian flags are not really beautiful. I think it is the black which makes them look stupid. The Antwerps flag isn't bad, it has a kind of optimistic atmosphere.
When I was a little child my parents went to Belgium with me for vacations. I wondered why they had so many German flags hanging around there. Much later I discovered that it was the Belgian flag that they had in Belgium

And it's quite different: The colors are in a different order and the stripes are upright. Even the colors are not the same: The Belgian one has yellow, the German one is supposed to have a golden stripe (though this is hardly visible on most flags).