Can you guess what the single biggest complaint people have at restaurants is? I'll give you a hint: it's not the food . What diners grumble about more than anything else, per a recent study, is bad service . And this comes as no surprise, at least not to me. Bad food -- whether it's soggy fries or a steak that's a tad rare -- is more forgivable in that the waiter or waitress can simply bring you another item. Restaurants get busy, especially on Fridays and Saturday nights. No harm, no foul. But poor service leaves an indelible impression -- a bitter taste in our mouth. I recently went to an Outback restaurant and had one of the worst dining experiences of my life. The waitress never came around for refills and forgot to bring me ketchup, mustard, and mayonnaise for my burger. My friend complained that this soup was cold and he requested that she heat it up for him, to no avail. Needless to say, we asked to speak to the manager, after which we received wh...