When Nan's sons were small she had a night time job as a nursing auxiliary in a local hospital. She would put the boys to bed and then cycle off to work, coming home in the early hours to catch a few hours sleep, get them up for school and then cycle off to her day job.
Nan arrived home, exhausted and staggered into bed, within seconds she began to scream loudly as her feet met the furry bundle that objecting to being woken attached claws to her calves. Nan was not amused and often referred to this episode as if on level with matricide. When asked which cat it was (well - this detail was important to me) she would say: 'How should I know - all cats are the same in the dark.'
When I was older I looked up this saying - big mistake- and chanced upon Benjamin Franklin's advice to a young friend - I was quite glad that this Nanism/Franklinism hadn't become part of my vocabulary.