Our nearest Mercadona supermarket in Santa Cruz de Tenerife was renovated for the past 3 months, and was reopened last week. Today I went there without my headphones, very unusually, and that was great, because I noticed that they had acoustically treated the whole market very well! The whole ceiling was tiled with sound absorbing tiles. And additionally, the background music had been turned way down, it was barely noticable. It felt much calmer than before, just because of this.
I'm really glad they have done this, so big thanks to Mercadona for investing in my well-being!