My girlfriend's weird little Westie will not let anyone trim her toenails. She has a distinctly neurotic phobia about it. When the clipper comes out, she just starts trembling and shitting. No body knows why. There was no traumatic experience. She's never had her nails trimmed at all, but she knew what the clippers were for from the beginning because the other terrier in the house, a Cairn, gets it's nails clipped regularly.