Umm... because when Starbucks opens a new coffee shop, the local indepandant shops lose business and are often forced to close. That's like, someone's job and livelihood gone. The varying characters atmospheres are also lost... Starbucks coffee shops all look the same; what's interesting about that?

Starbucks, despite all the "ethical" crap it comes out with, like so many other huge corporations, is as far as I know, is still taking part in unethical practises like unfair trade with coffee farmers who could really do with the money. They're very keen to tell you with a glossy marketing campain how much they support fair trade coffee, but only about 6% of the coffee they sell is fair trade. :/

Yes Starbucks may well soon be the "best" coffee, but only when all the other coffee shops are closed. For now I've had plently of better cups. :]

(If you want more coherent reasons it's better to search for it, there are sites on the interenet which explain it better than I could. )