Just because it’s someone’s job doesn’t mean you have to act like it.
You don’t have to say “please” and “thank you” to a waiter. They’re going to bring the food no matter what. But if you’re nice, if you treat him like a person instead of a server, don’t your chances of getting better service increase?
I’ve noticed this over the years working with students. Every kid at Collegewise gets advice, and we’re nice to all of them. But for the students who are particularly engaged during their meetings, who sincerely apologize if they miss an appointment, who are appreciative of our help and of their parents’ willingness to hire a counselor, we’re going to be even more invested in their success. It’s not a policy. It’s just human nature.
It’s your teacher’s job to help you when you don’t understand. But doesn’t she still deserve a sincere "thank you" when she stays after school to meet with you?
It’s your counselor’s job to send your transcripts to colleges you apply to. But doesn’t she deserve to be given plenty of time to send them (and to get her own appreciative "thank you")?
It might be your parents’ job to drive you to baseball practice, pay for tutors, and make sure you have a hot meal every night, but don’t they deserve to be treated like family instead of employees?
Treating people like it’s their job makes them want to do just enough not to get fired. And nobody’s ever raved about that kind of service.