Pets offer lessons in life, and death. They're often the first introduction a child gets to death-- that mysterious, eternally heartbreaking idea of whatever life is being stripped away. We will never accept it completely.
A pet is our friend, one so innocent and so loved. When you know that the moment is soon coming, your heart is crushed and your eyes are wet. There's nothing you can do, and you know it, and you hate yourself for it.
Eventually, if death is not in a hurry but taking its merciless time, you do start considering quality of life. You think more about their suffering, not how sad you are. You force your weary feet to make that harrowing trip to the vet, and return with a shoebox for a coffin, and family car for a hearse.
You bring your friend to a nice place, maybe among some flowers, maybe under an old tree, and you start to feel a little better, because you know that they are too.

We brought home a litter of kittens today, and the runt has stolen my heart! Boudreaux, as I call him/her, is black and white, his black face amplifying his white whiskers. There are seven kittens total, but mama cats only have six nipples. Boudreaux is thin and scraggly, but he's eating more than the others.
My sister saved them from a condemned building, spending the entire day collecting the kittens then resetting the trap. The place was falling apart and mold was growing on the wall, piles of rubble serving as thier homebase. They're now huddled together on a blanket in a box on the porch, yet they're probably more scared here for the moment than they were back in that suffocating building. But they'll calm down, I believe. We already have homes lined up for them.
Save something innocent every once in a while. It's good for you.

Ok, so what's the deal with rude drivers? Are their lives really so horrible that they have to spread around the bad mood to everyone else? Everyone has stuff to deal with already, but people with selfish tendencies make sure that everybody and their brother a know that they're upset.
So let's try to polish something so that it comes out a little clearer: Rudeness brings rudeness, kindness brings kindness.

So can we just be nice to eachother? Please?