Maybe it is a dangerous habit to instruct entities in plain English without anthropomorphizing them to some extent, without at least being polite? It should feel unnatural do that.

Yeah, my instinct is that we're naturally going to have emotions resulting from anything we interact with based on language, and trying to suppress them will likely not be healthy in the long run. I've also seen plenty of instances of people getting upset when someone who isn't a native speaker of their language or even a pet that doesn't speak any language doesn't understand verbal instructions, so there's probably something to be said for learning how to be polite even when experiencing frustration. I've definitely noticed that I'm far more willing to express my annoyance at an LLM than I am another actual human, and this does make me wonder whether this is a habit I should be learning to break sooner rather than later to avoid it having any affect on my overall mindset.

It does feel unnatural to me. I want to be frugal with compute resource but I then have to make sure I still use appropriate language in emails to humans.

This. Right now, I'm assuming you're all humans, and so are all my coworkers, and the other people driving cars around me and etc. How easy is it to dehumanize actual humans? If I don't try to remain polite in all written English conversations, including the LLMs, that's going to trickle over to the rest of my interactions too. Doesn't mean they deserve it, just that it's a habit I know I need to maintain.

You're only polite out of habit?