I'm sorry to all the folks who have recently lost a pet and to those who have lost them in the past in unfortunate circumstances. Losing a pet is like losing a human loved one. It's not just A cat or A dog, it's YOUR companion.
I remember the first time one of my pets had to be put down. He was an old dog and he had a long run, but I remember coming out of the shower and my mum, tears in her eyes, said "Come and say 'goodbye' to Tom." I got dressed and held him for a very long time before my father put him on a leash and took him to the vet's. When I was embracing him, he licked my ear and wagged his tail even though he had a severe case of arthritis.
The second major experience I had was when my dog Woody had to be put down due to health complications. Some days he was full of beans, others, he vomited and didn't have an appetite and could barely move. One day he collapsed while I was hanging out the washing and I rushed him to the vet's only to be told that he was on his last legs. I don't know how this happened, but the vet told me to take some time to pat and cuddle him before he had to be put to sleep. To this day I don't know precisely what it was that made his health degenerate that way, but nothing could change the fact of how upsetting it was for me.