Line from the theme song of Mystery Science Theater 3000, which encourages the viewer not to worry about details that are irrelevant to the enjoyment of the program. Sometimes referred to as Hodgson's Law, after Joel Hodgson, creator and original lead actor of MST3K.
The full line, used more rarely, is this:
And other science facts
Then repeat to yourself 'It's just a show,
I should really just relax.'"
Take three deep breaths and recite when tempted to make a Justifying Edit. Many of our very own tropes (including and especially our Artistic License archipelago) have a tendency to get very nitpicky about following or failing to follow core sciences so even we could do with repeating it to ourselves regarding whole tropes.
TV scribe Michael Reaves simplifies the sentiment even further: "It's only television."
When we consider that the very point of MST3K was itself to mock and ridicule movies for breaches of logic and defective storytelling, we encounter a sort of MST3K 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 MST3K was little more than a goofy premise to facilitate the mockery of bad movies, and labelling this as "just a show" doesn't make it any less good. note
On the other hand, anybody who hopes to promote a movie and insists 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 is insulting the intelligence of the audience. This is not about critical appraisal, but what is necessary to tell a story. When criticism targets those things that were simply unexplained, only then should you invoke 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 is Older Than Steam, also being used in William Shakespeare's A 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."
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."
Waldorf: Key word, "should." They never said we have to.
Statler: Good point. Hey, Cambot! When you look in the mirror, do you tell yourself to "say cheese"?