The same when driving, "are we exiting on this or next exit?"
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.
Language is not easy and full of ambiguity, which is why language majors haven't taken over software development
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".