Knitting & Crocheting with Novelty Yarns

Has this ever happened to you?
You're indulging in one of your favorite pastimes - shopping for yarn at your local craft store. Next to all the nice, reliable-but-dull worsted weight you find other yarns that tempt you with colors and textures you've never seen before. You pick up a ball and feel how soft it is. You think about that pattern you've been saving, waiting for the "right yarn," and you decide you've found it. So you buy a few balls, take them home, and settle down in your favorite chair for a couple of hours of relaxing, creative needlework.

An hour later you're sorely tempted to throw that yarn across the room (or maybe you already have). At the very least, you'd like to return it and post a "stay away" warning in the store; you know you'll never buy it again.

What went wrong? How did this "beauty" turn into such a "beast"?
What is it about novelty yarns that pulls us in and then turns against us?

How are novelty yarns made?
Novelty yarns have been around for many years, but lately they've been showing up in greater quantities - and varieties. It seems that commercial yarn technology has improved to the point where it's no longer cost-prohibitive for yarn companies to make them. Also, this same technology can be used to combine individual novelty yarns to make a completely new one. Eyelash, ribbon, and thick-and-thin yarn have been around for quite a while, but now you can buy yarn that has a strand of more than one type - for example, eyelash yarn twisted around a strand of ribbon. This makes for some really interesting effects. But for the person who actually wants to make something with it - rather than just admire it on the shelf in the store - it also combines the most frustrating qualities of each.

A summary of those "frustrating qualities"
First of all, this yarn can turn out to be thicker - or thinner - than it looks when it's all wound around itself on the ball. When you start to unwind it, you suddenly discover that those size 8 needles you were hoping to use won't even come close to giving you the effect - or the gauge - you want. You really need size 11s, 13s, or larger.