If dying is such a trivial thing to you, I suppose your beloved cat or dog dying wouldn't bother you much. I suppose you dying wouldn't matter to you much either. Except it does, and it does for all living beings. All of them fight for their lives.

In the case of slaughter, it's unfortunately not over quickly. I recommend watching the movie Earthlings to see standard slaughter practices.

Animals actually do miss each other, and they value their own lives. I recommend reading the book "The Pig that Sang to the Moon" for more information on farmed animal behavior, thought, and emotion.