Which mainland European countries have epic free public toilets as a rule rather than as an exception?
I'll admit it's possible these countries exist, just that they aren't any of the ones I've been to.
Since the mainland European countries I haven't been to are mostly either microstates (which I'm not counting) or post-Soviet, I doubt your claim.
Personally, I rather enjoyed the roadside German toilets. Though they aren't free. But for a small fee you get a reasonably clean toilet while driving somewhere.
Worst public toilet experience in Europe? Hands down, Bulgaria. Sorry, Bulgarians, I love you guys, but your toilets....... Ugh!
A washroom at at an Irving in rural New Brunswick will have the same weird smells and nonspecific grossness as a Petro in North Vancouver.
Granted, I also haven't visited most of Europe since being a kid, though at that time I remember a few Orlans in Poland and Elfs and Mobils in France having a much cleaner vibe than the gas stations back home.
I’m not above admitting I’m not up to date on how the public washroom situation in the rest of Europe has changed in the past 15-20 years, though.