There are spiritual perspectives that say there are no "accidents". "If you pick up the pot, you pick up the handle." Even our deaths, the way we die, all the suffering that we experience is there because of something we have set into motion.
Then there is the perspective that all we experience are lessons we need to learn.
I don't know what the answer is, and I'm less convinced there is a single answer. I do love hearing all the other perspectives however.
I certainly agree with the points you make Jacqueline about us being the product of the events we ourselves set in motion and the experiences from them, good or bad. I think they all deserve thoughtful consideration. As for my pets, I don't believe there is any gain from suffering that I can put my finger on. Yet I have often had overwhelming feelings of guilt when having to have put one to sleep. I have witnessed the same look that indicates to me I am betraying them by ending their life prematurely, despite their suffering. It all gets very confusing sometimes.