As someone that shopped at both, but preferred Circuit City, I think Best Buy initially did a better job of “wowing” customers and had a better store layout. They also were better at trying to squeeze money out of people and thus were more profitable than Circuit City, so when times got leaner they survived and then had the whole market.
Minor correction: You can’t say no because they intentionally almost never give you “no” as an option. It generally is “Ask again later” instead, when you clearly never want them to ask again, just like you didn’t want to be asked the first time.