My family went out to Thanksgiving dinner this year. We ate at a place that served family style. The waitress brought us plate after plate piled with delicious fare: turkey, stuffing, potatoes, peas and carrots, rolls and salad grown locally. With such massive amounts of food, I had big plans for dessert.
However, when she brought out the pumpkin pie, there was only enough for each of us to have a small square. Given how full I was, I probably didn't need more than a bite or two. However, I was disappointed, thinking I would also receive as much pie as I could eat.
The lesson here is--when setting customer expectations--don't start big and end small. All the customer will remember is a disappointing finish.