To he fucktard who feels like he wants to Van Damme people on the bus, you're an asshole.
My dog is small and I have disability where I have the need for a service animal. She may be small and can sit on my lap, but she has training and certification which by law I am not required to show you or anyone else such documentation. She is a working animal and she has saved my life. In no way are there size requirements for working dogs at all or a federal law on what breeds can or cannot be used. I have even seen a dog from the pound with no training whatsoever who has detected low blood sugar in a diabetic before the human even knew it. That dog is a lifesaver.
As for the fucktards with seven kids and SUV strollers etc, I agree with you there. But please don't lump all the animals you see that aren't a Labrador as bullshit. That animal may have a use you have never heard of.