A rather bad habit I have picked up over the years of my undergraduate studies is procrastination through the use of television. Part of that stems from the ubiquity of shared media while living in residence, while another part comes from my attempts to limit by game playing (and thereby hopefully promote more work) by supplanting computer games with a less open-ended and somewhat easier to control habit (watching television). While the efficacy of my methods might be somewhat in question, the end result is I have watched a fair bit of television over the past few years, and part of that has involved watching a great deal of the various Star Trek series.
The thing is, calling Star Trek science fiction is a bit of a misnomer, as it is more of a fantasy that just happens to be set in a future which purports to share our history. It includes magic (like telepathy) and technology at best only tenuously connected with our actual understanding of science. Accepting, then, that Star Trek can be given the same leeway one gives to other tales like The Lord of The Rings in that it exists in a universe apart from our own and thus can be accepted as functioning on its own system of rules, it should at least be consistent with itself. When I was younger and contemplated pursuing a career as an author (I know, I'm a tremendous dork. While normal adolescent boys dreamt of becoming rock stars like Kurt Cobain I dreamt of becoming an author like Isaac Asimov), one of the things that was appealing about writing fantasy novels was the idea that I was in control of everything. However, given my brain's propensity for over-obsessing over small little details, there always had to be an underlying system to the way things functioned in my world, and therefore I would make up elaborate rules for the applications of things like magic such that I would always be consistent without the arduous task of rechecking all my previous work (I'd just have to follow my own rules). The way I viewed it, when you get to make stuff up, you should at least make every possible attempt to stay consistent, at least as a courtesy to your readers (or viewers, in the case of Star Trek).
While I recognize that there are certain things that are going to be overlooked across several seasons and several different spin-offs, there are certain things which I think at least someone should have thought of at some point. To avoid ranting for too long on the subject, I am going to bring up perhaps one of the most obvious ones: the Universal Translator. This handy little device (which it is unclear where it exists, just that it seems to always be available to the characters, with the notable exception for a trio of Ferengi who accidentally went back in time to the 1950s) allows everyone to speak the same language. Accepting that it works and not worrying too greatly about the details, how then do Klingons somehow still purposefully revert back to speaking their own language in particular and well-chosen circumstances (almost always just for short little things like "Kapla" instead of "Goodbye")? Why isn't that getting translated by the handy little device? Most offensive are the scenes where there are only Klingons present and they spend the majority of the scene speaking English, but then, often for dramatic purpose, one will say something in Klingon (this seems to happen a lot when Worf is hanging out fighting some sort of war on Klingon ships).
Anyway, I propose the following: if ever any reader of mine is in charge of the production of a science fiction show with a widespread and ludicrously dedicated fan base like that available to Star Trek, create a position on your writing staff for one or two of those insane fans to proof read your scripts and look for internal inconsistencies. You could probably even convince them to do it for free (maybe they get a souvenir from the set or something like that).