Most of the dogs I've had resisted having their feet touched, even though none had ever experienced injury or abuse. The last two have been different -- both Labs from the same breeder. Part of her process is to handle the puppies from as early an age as prudent, touching and petting their feet & ears to acclimate them. This comes in really handy for cleaning, nail clipping, drying wet feet & ears, etc. Our current Lab will alllow anyone to hold his paws and pet them.
We've always done our own grooming. The first few dogs kept their own nails short from walking on pavement. As we've "matured", we now take our dogs to the park for runs, which necessitates regular nail clipping. We found that doing it immediately after a bath -- when the nails are still soft -- is much easier on them and us.
I wonder if they are ticklish?