The tap was in Athens was, for us, extremely good tasting. We found ourselves constantly drinking the water, it was actually a treat to drink. We found it far better than either our own tap water, or the bottled water (Ein Gedi) that we bring with us when camping.
That Penn & Teller YouTube link even has a section showing this, though you only need to go to the supermarket and look closely at the fine print of all the different brands of bottle water. You'll quickly find a lot are tap water.
I’ve lived in places with tap water that is definitely noticeable vs filtered/treated water. San Jose water for example is extremely hard and I suspect few people would mistake it for bottled.
https://www.wine-economics.org/aawe/wp-content/uploads/2018/...
Many people have become familiar with the flavor of plastic, and learned to associate it with “purity” or “freshness” or “quality” or whatever.
In NYC I always drink bottled water, where I’ll happily drink potable tap water in most places.
They claim it's for the taste and purity.