You put it well, and quite wisely, I think. Since each relationship (and each situation) is unique, one ought not have a firm, fixed "tipping point." One size may not fit all.
I did think of the Prado. It has a most excellent selection of Velasquez, no? But since you asked how, here's how: I couldn't recall the exact name, and I knew it wasn't simply "Prado." In fact I had that in particular in mind when I added the last option, so please don't feel slighted.
You're quite right, John, there's one I forgot to include. Although there are certainly many others as well. The Vatican's collection is world-class by any definition.
You've got all this music, all of which you've heard before, and any of which you could select to listen to at any moment. And yet, using the Shuffle feature makes it more fun and exciting, doesn't it? Why should there be some element of surprise, when you've already heard it all (often many times) and you loaded it in the first place?
Even though it's no fair peeking, here's what's coming up next on mine:
Glad All Over - Suzi Quatro Punk Sandwich - The Dixie Dregs A Dime Away From A Hotdog - Oscar Brown Jr. The Largest Elizabeth In The World - The Roches Love's Been Rough On Me - Etta James
What's coming up next on yours, and does it spoil it somehow to know in advance?
Here's a couple. Rick Derringer's "Rock and Roll Hoochie Coo" is actually a cover of a song he wrote & recorded earlier when he was with The Edgar Winter Group. Likewise, Todd Rundgren's "Hello It's Me" was recorded by his earlier group, Nazz, and then again by Rundgren as a solo act before his third dart finally hit the bull's-eye. And though few know it, Harry Nilsson's classic "Without You" is actually a cover of a Badfinger song.
I think Joni Mitchell's an enormous talent, and the entire host of today's female singer-songwriters owes her a huge debt. She's a gifted artist. And speaking of art, y'know she does all the art for her own album covers, too?
RE: When to draw the line?
You put it well, and quite wisely, I think. Since each relationship (and each situation) is unique, one ought not have a firm, fixed "tipping point." One size may not fit all.