Yeah, the "weekend-ness" of Friday is interesting. Actually I could extend that to the last couple days, in relative time. For example, if it's Thursday, and I said "last Monday", that would actually be kind of confusing, just as if it were Sunday and I said "last Friday". I'm much more likely to say "On Monday," or "On Friday," if it's within the current week or the current weekend, and use the sentence context to figure out if I meant the previous weekday or the upcoming one.
I'm glad I don't write either dictionaries or voice-based/natural language apps for calendar appointments. ;-)
After writing my previous comment, I keep coming up with exceptions and variances to those exceptions. Like—as I write this—I would refer to June 9 as "this Wednesday", but June 11 as "next Friday". So I suppose I "glue" Fridays to the weekend? And right now it's still the weekend so June 4 retains the "this" title until tomorrow?
Starting to feel like I have epicycles of rules similar to the adjective ordering we all know, but never explicitly learned ("big red bouncy rubber ball" is okay; "bouncy red rubber big ball" is NOT OK)