Computers exist to serve. Anthropomorphising them or their software programming is harmful¹. The tone of voice an officer would use to order a private or ranking to do something seems suitable — which obviously comes down to terse, clear, unambiguous queries and commands.

Besides, humans can switch contexts easily. I don't talk to my wife in the same way I do to a colleague, and I don't talk to a colleague like I would to a stranger, and that too depends on context (is it a friendly, neutral, or hostile encounter?).

1: At this point. I mean, we haven't even reached Kryten-level of computer awareness and intelligence yet, let alone Data.