I have lost a few cats over the years to old age, and I can accept their passing easily since it was natural.
But there is one that still makes my wife and I teary-eyed; Slagathor. Before we moved to Seattle, we had four cats. Two of them were brothers ~5 years old but still acting like overgrown kittens, and we had no problem re-homing them. One was in her late-teens (no less than 16, and likely older) and in declining health, so we had no problem having her put down since she wouldn’t have lasted more than a few more months anyways.
Slagathor, however, was a 10-year-old cat in great health. Very intelligent, very loyal, but she had anxiety issues that, coupled with her age, made her impossible to find a home for and also impossible to bring with us. She “cracked” a bit when her sister died from kidney failure, and we are sure that the cross-country move would’ve destroyed her; if we could’ve brought her along, it wouldn’t have been the same cat we had when we left NH.
I was the first human that Slagathor saw when she opened her little eyes, and she died peacefully in my arms seconds after the vet put the needle in.
R.I.P. Slagathor :(