When I spent some time in Spain after learning Latin American Spanish in the US, someone told me that there are two times it is acceptable to use the usted form in Castillian: with the royal family, or when offering your seat to/helping an old person on the subway. Otherwise, you risk implying that you think someone is old or sounding sarcastic. Basically, the usted form is almost never used in Spain, and the tu form will be used in most employee employer relationships, so this sentence would be perfectly normal.
Meanwhile, in some places in Latin America, the tu form will never be used when talking to a person of the opposite sex, even among married couples.
I would imagine, in much of Latin America, this sentence would imply a certain level of intimacy to this service.
So the form you use is really dependent on the Spanish dialect being spoken, just as much as the relationship between the speakers.
¡No!¡No!¡No! ¡Y mil veces no! You can say 'usted' to all people, it is a courtesy form, and the courtesy IS very important. Who had told you that?
It is true that nowadays the young people is forgetting the good manners, but I get angry when a person some decades younger than I tell me at shops: "¿Te puedo ayudar?" NO, It is "¿Le puedo ayudar?"
Remember: Goods manners ;-)
It seems that way from everything I've read. Siempre always(lol) seems to be at the beginning of either the sentence or the clause within the sentence that it is referring to.
English construction - I'm always late for work!
Spanish construction - Always I am late for work!