What's the experience of neutering your cat?

Last week, my kitten was sterilized. At that time, the kitten was lying in bed and drugged. He slept soundly during the operation. At that time, when the doctor operated on it, I cried at the bloody scene. After the operation, when I brought it home, I felt it looked at me with a melancholy look. It's pathetic, and I can't bear it.