What is it about yarn?

What is it about a yarn that turns out to be more expensive and harder to find than it seemed at first? I have a bunch of balls of Filatura di Crosa Luxury yarn. (Luxury is the name of the yarn, not a value judgment on Filatura di Crosa.) I don't particularly like this yarn, even though it's 100% silk: it's fingering weight but it's 5-ply, which means that unless you're watching the knitting very carefully it tends to split. It's very smooth, but for some reason in most lights it just looks like a cheap cotton, not a silk (although as soon as you touch it you realize it's too smooth for cotton). What is the point in knitting with yarn that looks like a cheap cotton, but is much more expensive? And the colors I have aren't great: I have a couple of balls of white, a couple of balls of a dark beige, and a few of a lighter beige. Until about ten minutes ago, I figured I just need to find a good way to use this yarn up and make room for better yarns in my stash.

Then I started experimenting with designing some lace patterns (just because I finally have time to do that!) and I thought that I could use the yarn to experiment on. It's natural fibers, its smooth, and it's a light color, which means it would show the pattern well. I also thought that I'd look it up online, in case I wanted to make a shawl out of it (to use up what I have) and needed a couple of extra balls. I had bought all of the yarn in various sales (it's a long story) for an average of about $2 a ball. It can't be that expensive online, right?

Wrong. The only place I could find it was in the largest online yarn stores (most don't even carry it anymore) at $18.50 a ball. And, suddenly, I'm loath to use this yarn. It doesn't matter that I curse it constantly while I knit with it. It doesn't matter that I think the colors suck. Now I'm looking at the yarn and thinking "is experimenting with it really worth it?"

But I am going to be strong. (Yes, I will, and don't look at me like that.) I know I don't like this yarn, and that I will never knit with it unless I really really have to. Thus I will experiment with it and ignore my irrational back-brain which makes unhelpful comments like "but you won't be able to get more!" (regardless of the fact that I don't want more) and "but it's so smooth and nice to knit with!" (even though, although it is smooth, it is not nice to knit with). I will make it. Just watch me.