What I find strange in Paris (or France) is that all expressos in any café taste exactly the same. It's not absolutely bad, it's a little bitter and quite strong; but why is the taste so consistent?
Food products are usually not consistent; nothing can be more different than baguettes or croissants coming from different bakeries for example.
I have zero actual information about this, but would imagine it's because all cafés get their equipment and coffee from the same vendors and never try anything else...?