I'm planning on picking out a really scrawny horse for my overweight cousin the ride.
Why would you do that to the poor horse?
I think it would be hilarious.
You want to chose a small animals for a big person ride, how sad is that. Not sure why you think it is okay for that to occur, the animal is going to suffer most. The animal needs a lighter person to ride, get this mindset out of your head already.
I don't see what's so bad.
The reason why it's bad is because you could injure the animal by doing this. It's not worth hurting the animal just to get a little laugh out of it. Take some time to think about this, I think you'll know where I'm coming from.