It costs less to keep a good customer than to acquire a new customer, which is why so many companies seem to focus either on keeping customers from leaving, or on making customers want to stay. Though the two approaches sound the same, realistically they're quite different and produce drastically differing outcomes.
An American Express 2011 survey found that 75% of customers think they get better service at small businesses, and an overwhelming majority say small local businesses are key to their local economy. The conclusion: at least three-quarters of your customers want that "small business" feeling.
We're not going to discuss just technical issues on why people leave your site. Why not? Because it's easy and fast for a webmaster to identify bugs in the code and is (typically) easy to fix, but conversion "leaks" are harder to spot.