1. They are made of sheepSKIN. This means the sheep is slaughtered for the sole purpose of making these boots. Some may think the sheep goes "unharmed" in the process of making UGGs, but there you have it. They kill them, so celebrities and fashionable people can wear them. Of course they are good quality, but would you really want to walk around with a dead animal on your feet?
2. They are SO expensive! I've never been a girl for fashion brands, really. I'm not saying I'm a cheapskate, I just don't see the point in paying hundreds of dollars for a pair of boots, or a sweater, or a pair of pants or whatever.
There are plenty of animal friendly UGG-like boots out there. You can for example get a lot of faux fur boots or vegan boots. Amazon.com offers a variety of these, just type in "vegan boots" in the search field :)
I also came over this article, thanks to one of my friends on facebook; http://www.peta.org/issues/animals-used-for-clothing/wool-industry.aspx
There is a whole lot I don't know or haven't researched and I didn't know this either. It makes me want to stop wearing wool altogether. My impression of the wool industry has been set in my mind from when I was a child, and I watched programs and stuff where they shaved the sheep and it didn't look nearly as violent as described in this article. But then again, I was a kid, I didn't think about the "secrets of the wool industry".
I am not a vegan/vegetarian, and I know there's no excuse in saying "but that doesn't mean I want animals slaughtered". But at least I want to contribute to the cause by not _wearing_ the animals. I barely eat red meat, in fact I'm thinking of quitting it altogether. The only thing I could never ever quit eating, though, is fish. If I cannot become a vegetarian/vegan, I could be a pescetarian. Or at least eat less meat :)