I love to observe any kind of service animal at work. However, I am careful to never distract or talk to the dog. The dog may become excited and pull on his handler in order to meet me. I speak to the handler and not the dog. I never ask what their disability is, but I do ask if they would be willing to share with me what their dog does for them, and if I could help them with something.
Please do not distract assistance dogs in any way. You may accidently cause harm to an innocent person.