To be protectable, trade dress must be nonfunctional and distinctive. A great example of nonfunctionality is seen at right. The shape of the Mrs. Butterworth's pancake syrup container is completely nonfunctional. In other words, the shape of the bottle serves no purpose when a consumer pours the syrup on food.
Nonfunctional trade dress will usually be distinctive and thus protectable. If a company does not protect its trade dress, however, nonfunctional trade dress could be determined indistinct. For instance, see the Sue Bee Honey container at left. Much like the Mrs. Butterworth's bottle, the shape of the bottle serves no purpose when a customer pours honey on food. Provided it is source-identifying, the honey container would also be distinct and thus protectable.
By itself, the honey bottle is distinct, but there is a Des Moines barbecue restaurant that stores its barbecue sauces in empty honey bottles and serves them to customers. Allowing another company to do this diminishes the likelihood that you have protectable trade dress in a court of law, because you are allowing another company to be associated with your honey containers.