You can slice your dog wide open with scissors. Especially if you are cutting through mats with scissors. THAT IS A HUGE NO NO!! You have to hold shears a certain way to avoid injuring the dog. There are areas you NEVER EVER use scissors on.

Oh owners hurt their dogs all the time. Clipper burn. Slicker burn. Bruises from combing out mats... You can nick a dog with clippers. You can clip the tongue. Catch a dog in the eye with scissors. Slice the ear leather. Split an ear combing out mats. There is a reason why GOOD groomers cost money. Went to school for 6 months and apprenticed for a year before I was allowed to fly solo.

Also we hate having the owners around. The dogs are ten times harder and do not focus upon what the groomer is asking. And the owners tend to step in and "save" the dog which in turn makes them act up ten times worse the next time.