Because the carefully painted toenails reminded you that the abstract 'piece of meat in a freezer' had only recently been a feeling and cared for part of someone. But you probably know that already.
I had to get used to a lot of 'gross' manifestations of death and decay during my mother's dying process two and a half years ago. I now push those images out of my mind and try to remember her as the beautiful woman she was.
On a different note...I recently started up a worm composting bin in a corner of my kitchen, and I had been a tiny bit apprehensive about handling a pile of squirming worms in my hands. I have enthusiastically raised snakes, tarantulas, and various creepy-crawlies in my day, but a
solid mass of worms were something new to me.
Not that I 'had' to hold them in my hands, but I felt if I were going to raise worms then I should not be afraid to get my hands right into them. I was pleasantly surprised when the 1000 worms arrived and I dumped them on the table- I quickly got over any squeamishness and in fact they felt kind of pleasant, all wriggly slowly as a mass in my hands. Not slimy or gross, more smooth and cool feeling.