Honor Before Reason: While it has occasionally been claimed about the Empire (mostly by people who have more experience with I Gave My Word than with their Combat Pragmatism, which is more confusing that enlightening on that point), if you were to ask – or observe – an actual Imperial on that point, they would point out to you, and support with a small pile of ethical calculus, game theory, etc., that given a couple of preconditions, namely:
That your values are slightly more sophisticated than mere survival – and actually, quite a lot of the time even if they are only mere survival – or shameless backstabbing fuckery for its own sake;
And that your honor-code is well-developed and comprehensively thought through, honor being cognate to neither stupidity nor thar;
Then honor is reason, the apparent lack of practicality is functional if you take the time to look at the Big Picture and iterate, the apparent denial of a value may well satisfy a metavalue, and the entire question that the existence of this trope presupposes is invalid. So.
(Of course, this still looks very much like playing it straight to people who are less, ah, willing to do whatever is necessary to abide by their extraordinarily valued principles/values/metavalues. To plagiarize the applicable line from Dragon Age II, “What would the eldrae be without principle? You, I expect.”)