- It's portable and requires no electricity, unlike laptops, PDAs, and cell phones. If you're standing in line or waiting for something, it's easy to pick it up, make a little progress, and put it down again.
- It's a fairly inexpensive hobby. Oh, sure, you can get in deep if you're buying lots of patterns and very fancy yarn, but it's easy to keep it modest, too.
- People tend not to get offended by it. Depending on the title or topic of a given book, it's possible to get disapproving looks while reading. Not so much with crochet.
- It's very forgiving. You can do it while doing other things, like watching television, talking on the phone, or hanging out with old friends who are comfortable like that. It doesn't require much concentration, and if you blow a stitch, just pull it back out and redo it.
- Crocheters come from all walks of life. It's very inclusive in that regard. Abandon any preconceptions you might have: from geek to granny, from soccer mom to trendy hipster, crocheters come from very diverse backgrounds.
- It's quiet. You can crochet without bothering anyone else.
- It's a productive hobby. When you finish a project, you have the reward of tangible results. Often, these results provide joy to others in the forms of gifts and keepsakes/heirlooms that will last a lifetime and beyond.
I know the same things can be said of knitting, but I haven't learned how to do that, yet.