It happens pretty often—pet owners who are confused about what breed of dog they have at the end of the leash. It can be humorous, or it can cause problems.
Here is an example. A customer calls and schedules an appointment for a Pomeranian. You set a date, planning how long it usually takes you to groom this breed. The customer shows up with a 48-pound dog that looks a whole lot more like a Chow mix than the Pomeranian you were expecting. Your schedule for the day takes a painful hit. This dog is much bigger and fluffier than you had planned on. On the other paw, sometimes you get lucky. A customer might make an appointment for a 50-pound Doodle and come in with something that resembles a slender Golden Retriever with very little coat. In this case, you might get to eke out a lunch break and put your feet up for a few minutes.
One way to help avoid surprises is to ask for a photo and weight when you schedule appointments. People are sometimes confused about what dog breed they own because a "breeder" or rescue organization has given them the wrong information. Of course, they are also occasionally vague about the animal's weight, but that is a story for another day.
It can get awkward talking to customers about breed confusion. In many cases, they are steadfast in their determination that their pet is a particular breed they clearly are not. I have found it does no good to argue with them. That jet-black "Maltese" with a wiry coat? It is usually best to smile and nod, then take notes to remember what to expect next time and move on. It does no good to make a customer feel defensive; if they are attached to the idea that they own a certain breed, just let it go.
Sometimes, however, you can give people a pleasant surprise. We groomed a lovely Field Spaniel several times before the owner called her a "spaniel mix." He had gotten her from a shelter and was told she was a mixed breed. I showed him a photo of a Field Spaniel in the AKC Dog Book, and his face lit up. He couldn't wait to go home and tell his wife they owned a purebred dog.
If the dog is larger and will require more work than anticipated, simply tell the owner you underestimated the size/degree of difficulty of their unique pet and correct any quoted time frames or money quotes you had given over the phone before they leave.
Keeping a list and photos of breed misclassifications can be kind of fun. The Cairn Terrier that is the size and shape of a Bassett Hound but has a wiry coat? The German Shepherd that looks and bays an awful lot like a Beagle? These can be gathered together to make a lighthearted scrapbook to smile about if you ever get a minute to sit down because the Cocker you were expecting is half the size you thought it would be and has a smooth coat.