Yep, It works up really fast. Granny Squares are easy and if you lose your place you can easily undo the mess up and just carry right along...of course they are forgiving too, If you didn't notice your goof it's hard to find the "oops".
You could use a smaller hook. Seems like I have used a J hook for a granny square blanket before....They get pretty heavy when you use a smaller hook so I would only use 2 yarns then.
My kids love it. It has TONS of holes in it since it's so large and the kids poke their fingers and toes through them!
You can even get creative with the colors...mix and match, make patterns of sorts. I use the variegated yarn. I think they're pretty. It's also a good project if you come across a yarn "sale". Especially if you like the color and feel of the yard but don't know what to make with it.
I'll have to say that we are blanket people though. We always have a blanket or 2 on the couches and we all use them to snuggle up with. I am wanting to find some of the "super soft" yarn and make a big blankie with it. I'm not that picky when it comes to the colors since we put up the blankets when we're done with them. (they don't have to match my room)
That colorful striped blanket is my son's. That was just a double crochet with a bunch of "left over" balls of yarn. I bought like 2 skeins of white yarn and just made each stripe as wide as I had yarn. I made a similar one for my niece using some girlie colors. They turn out cute and are really durable. My daughters used to love it when I would crochet barbie blankets for them. Those are like a 30min. Project with left over yarn.
I really just like to fiddle.