Angie's List spotlights the most talked-about business sectors in 2011

For any type of retailer, keeping customers happy is analogous to keeping business doors open.

For any type of retailer, keeping customers happy is analogous to keeping business doors open. As industry sectors become more crowded, businesses are relying on loyal customers more than ever for word-of-mouth marketing and repeat purchases.

To continue to please consumers, businesses must always be improving. With this in mind, the Angie's List report reviews business sectors, revealing the most complained-about elements and what consumers want.

"The good news for companies who provide great customer service is that consumers are sharing those experiences as well," said Angie Hicks, founder of Angie's List. "That kind of positive word-of-mouth marketing is invaluable to most business owners."

Banks and credit unions earned the No. 3 most complained-about position. However, this position may strike many as unsurprising, as large financial institutions such as Bank of America experienced consumer backlash in regards to new fee structures.

However, Hicks noted that some banks and credit unions have responded positively, listening to customers and adjusting their policies to take into account this feedback.