Oh, wow, that helped highlight my own hypocrisy.

I thought, "Obviously next Friday means 'not this Friday, but the one after.'" But, 'next exit' always means the most immediate exit to me. So I suppose 'next Friday' could reasonably mean the most immediate Friday, too.

After thinking a bit more about it "next exit" is the most immediate if you don't see any exits. If you are getting close to an exit you see and ask "is this our exit?" the answer can be "no, not this but next exit", or when giving directions you can say "not this exit, but next".

Language is not easy and full of ambiguity, which is why language majors haven't taken over software development

And you're always "in sight" of a Friday, so "this Friday" could always be in play :)

I suspect it's something to do with how we bundle days together into weeks. "Next Friday" really means the Friday of next week. It's even less certain when we talk about Mondays and Sundays depending on which day you regard as the start of the week.

Talking about "this exit" only makes sense to me when you are near an exit. If you're well in between exits, then I would think there is no "this exit". There's only the previous exit and the next one. I think it's normal for car navigation systems to say "take the next exit", when you're not there yet.

Applying the same logic to weekdays, if today is Wednesday, then next Friday is the one in two days. And one would never say "this Friday" since it can be called "today".