Something I have trouble remembering:

To someone for whom it is normal to choose words carefully and connote respect, it's obvious that this is the right way to go about things--it gets other people on your side, so you don't have to fight as much to get what you want or convince people of something. It's also more pleasant to be around, and is the way you wish to be treated.

To someone for whom it is normal to be as direct, clear, and efficient in language as possible, it's obvious that this is the right way to go about things--it's much more honest than insincere fluff and doesn't waste everybody's time. It's also more pleasant to be around, and is the way you wish to be treated.

The bit I particularly have trouble remembering is that neither person would believe that if their method didn't work for them. If you practice one of the above policies, I can reasonably assume that you get results from it which are acceptable to you. There appears to be a fairly strong division between people who have that experience with the former strategy, and those who have that experience with the latter strategy. Seeing that, I find myself wondering which of these scenarios is most accurate:

• Does one strategy work better for some people, and the other work better for other people? Each is certainly easier for different people, but I'm asking about results.
• Is the difference instead in the situation--so people who often find themselves in situations where one strategy is better prefer that strategy?
• Are these just two different tools which are both often valuable?
• Or of course, is it really just that one of these is a better strategy, and a lot of people are just so stuck to the other one that they won't accept it?

The reason I care about which of these scenarios is most accurate is that they change what kind of conversation about them is appropriate. If different strategies work for different people, then trying to convince someone else to use yours is unproductive other-optimizing. If they apply to different situations, it might be interesting to examine the differences in experience that lead to each preference. If they're both good tools, that suggests it could be worthwhile for each of us to work on the one we're worse at. And, finally, if one of them is actually better, we can carry on trying to convince each other of which one that is.

My intuition is that defaulting to courtesy, if it is not uniformly the more useful strategy, is at least more useful in the vast majority of cases. However, I do not trust my intuition on this, because that is the strategy which is much easier and more enjoyable for me to use. When I try to think of real reasons to hold that belief, other than "it's worked for me," two come to mind: one is that the courteous strategy seems like it requires more skill/effort (even people who don't prefer it seem to think so), and I don't see why that would have developed if it weren't valuable; the other is that I've read or heard several people (including the OP) say that they used to prefer the blunt strategy, but have learned to use and now see the value in the other one; I have never seen anyone describe the opposite experience.

If I'm wrong, I would like to be convinced that I'm wrong, and I feel strongly enough that I'm right that I don't think I can do that on my own. Here are some ways you could convince me:

• Describe a common situation where there is clearly more utility in stating x bluntly than stating x politely. Note that I don't consider the extra few seconds to say a few more words to be significantly detrimental to utility. If you can come up with one which is common for you but not for me, this will lend weight to the second scenario; if you want to convince me that the blunt strategy is really generally better, I would want an example that's common even when you're not, say, working in a technical field.
• Are you someone who is naturally inclined towards being more consciously respectful/courteous, but has switched to the other strategy because you found it more useful? What experiences led to this switch and what's different now that you've switched?