I'm Dutch speaker, we're known to be very direct, but I too believe adding "Please" in front of a request does not per se make it more polite. Another example that bothers me quite a lot is adding "Thanks" to a request without awaiting a reply. Writing "Can you please do xyz? Thanks" makes it come over as an instruction instead of a request, even though the author may have had the best intentions (express his gratitude). Or maybe I'm just overly sensitive ;)
One of the things I love about some European cultures is that they carry over their natural bluntness when they speak English, my partner is Hungarian and to English ears her way of speaking is blunt to the point of trauma, I think it’s great, I far prefer people just get to the point particularly when they are asking for something.
I am really not a fan of saccharine sweet false politeness.
With a Slavic language as my first, I generally feel like adding “please” or “thanks” makes a request canned-polite; essentially it distances the speaker from the receiver. That said, the effect could be adjusted with carefully chosen intonation.
Often a direct request would feel friendlier, unless receiver is particularly insecure/on the defensive. Sandwiching it between appreciative words is most foolproof, but I find it time-consuming to do in a genuine way.
