Courtesy of the inimitable James Lileks, trying to help Panera improve their customers' experiences:
Accuracy of your order. When you ask for coffee you get an empty cup and directions to the urn. The way the lady held out the cup so I could take it was highly accurate and professional.
Availability of the menu item you wanted. Well, I wanted calorie-free pizza, and they don’t have it, but that's my problem.
My personal rule of thumb is that a company from whom I've bought something moderately expensive gets three minutes of my time for their online survey. If five minutes have passed and I'm only 30% of the way through, it's 50-50 as to whether I blaze through the rest of the questions with deliberately misleading multi-choice answers and subtle abuse in the text sections, or I forward a ranting email to their head of customer service pointing out that they're not paying me for my time helping them, and if they want any useful information they can bloody well spend some time making the survey as short as possible. The bastards.