"It's just a show; I should really just relax."
Line from the theme song of Mystery Science Theater 3000, which encourages the viewer to not worry about picayune details that are unnecessary to the enjoyment of the program. Sometimes referred to as Hodgson's Law, after Joel Hodgson, Mystery Science Theater 3000 creator.
The full quote, used more rarely, is this: "If you're wondering how he [Joel/Mike] eats and breathes / And other science facts / Then repeat to yourself 'It's just a show, / I should really just relax.'" "Lalala"s optional.
Take three deep breaths and recite when tempted to make a Justifying Edit.
TV scribe Michael Reaves simplifies the sentiment even further: "It's only television."
When we consider that the very point of Mystery Science Theater 3000 was to itself mock and ridicule movies for breaches of logic and defective storytelling, we encounter a sort of dilemma; a glib assessment of the situation would have it that the show was hypocritical with its insistence that the viewers subject it to less scrutiny than they themselves brought to bear against countless films, but a more careful consideration should lead us to discern that different subjects should be held to different critical criteria. Indeed, what passed for plot in Mystery Science Theater 3000 was hardly more than a goofy premise to facilitate the mockery of bad movies, and labeling this as "just a show" does nothing to rob it of its value.
On the other hand, somebody who hopes to promote a movie can't insist it's "just a movie" and critics should "just relax" while also expecting they take seriously any aesop, speculation, spectacle, or anything else of potential value from it. Anyone who expects another to be selective of a work in exactly their prescribed way is insulting the intelligence of the audience. This isn't about critical appraisal, but what is necessary to tell a story. When criticism targets those things that were simply unexplained, that's when you bring up Bellisario's Maxim.
At the same time, however, one should be careful that they do not go too far and use this to justify saying that The Complainer Is Always Wrong. Yes, there's no point in getting excessively worked up and nitpicky about something that, at the end of the day, is just a work of fiction. But using it as a way of brushing off any and all forms of criticism is an equally dangerous attitude to have, and in creators can be a possible sign of a Small Name, Big Ego at work.
This concept Older Than Steam, being also used in Shakespeare's Midsummer Night's Dream: Puck's final speech, which starts "If we shadows have offended / Think but this and all is mended..." can be condensed into "'Tis but a play / I'faith, I should really just relax." This was actually a kind of disclaimer, to mollify people in power who may have construed the subject matter of that and other plays of his as blasphemous and obscene. It still applies to this trope, though.
In general, this applies to many philosophies, including the mantra of popular events, one being "It's just a week in the desert."
Or A Wizard Did It. The closest thing this trope has to Truth in Television is the concept of thought-terminating cliché: as The Other Wiki puts it, "a commonly used phrase, sometimes passing as folk wisdom [...] its application as a means of dismissing dissent or justifying fallacious logic is what makes it thought-terminating".
- Amusingly enough, the show did later provide an explanation for these, making reference to the equipment that creates the air, huge boxes of food, the Umbilicus (a space-elevator style hookup via which the Mads deliver things physically to the satellite) and a farm somewhere on the ship, which Mike never noticed.