While good service is a must for an enjoyable eating out experience, over-attentive waiters annoy restaurant goers. The guide's readers said that having your wine glass topped up every two minutes, or being interrupted to be asked whether everything's all right can ruin conversations. Restaurants not being absolutely clear about their charges is another customer bugbear. This includes restaurants not being clear about whether there's a coverage charge, or a charge for items that often come free, such as bread. Another sin on the list is restaurants asking diners to add a tip when a service charge has already been added. And according to the guide, if restaurants want to keep their customers happy they shouldn't charge for tap water. In a survey of members last year, Which? found that half couldn't taste the difference between bottled and tap water, with 18% preferring water from the tap. Other issues that made the list are bunched-up tables resulting in an evening spent eating too close to others, and restaurants asking diners to vacate their table before they are ready to leave. Opening salt and pepper bowls and restaurants that use out-of-season ingredients were also turn offs. Elizabeth Carter, editor of The Good Food Guide, said: "Dining out is usually an enjoyable experience, but sometimes a visit to a restaurant is memorable for the wrong reason, like an annoying waiter or a problem with the bill. Restaurateurs looking to raise their game this year could do a lot worse than listen to their customers' pet hates. They're often simple mistakes that can be rectified."