In the anime fandom, we have an ingrained idea that all shows can be measured by the same guidelines. There is a system that a lot of people follow called the “3 episode rule.” This states that for every anime you try, you should give it a minimum of 3 episodes to see if it is worth your time and is a good piece of media because it’s impossible to tell after one episode whether you really will like the finished product or not.
The earliest example of this I could find was in a forum post on giant bomb back in July 2008 entitled “My Journey in to Persona 4 animation: Ep 3” In this post they stated that “There is a rule that I go by when watching anime that if the show gets better after 3 episodes or shows signs of good development, it is worth continuing watching”.
Bar the fact that this post wasn’t proof written; they describe the rule in a way that is contradictory to how most anime are perceived to be produced; usually, an anime has a strong first episode to pull audiences in, and the quality could only drop from there. Even if it did get better from there you wouldn’t be able to see a massive difference with just two extra episodes, as the producers aren’t following this rule, and even if they were, it would game it, thus making it pointless.
Personally, I only use this rule for a small number of edge cases. The first is the idea of a flash-forward episode. This is where the first episode shows a section of the story that is past the initial introduction, to entice people into the world, and set expectations the audience can expect from the show. I am not a fan of this, as I prefer to be able to see a story from start to finish, and considering that is what you actually have happened in the rest of the anime it feels more genuine. A recent example of this was Saga of Tanya the Evil. I hated the first episode as it felt like a generic alternate World War 2 story with some magic involved, as magic makes everything better, but in episode 2, when they showed where the psychotic young main character came from, it ended up being one of my favourites of the season.
There is also the case of Osomatsu-san. Its first episode was just a string of parodies tied together with self-referential humour and constant changes to the art to the point where I thought that the show looked tacky, and wouldn’t be able to sustain itself but starting with episode 2, it turned into a slice of life sketch show, which is on the other end of the spectrum.
Finally, you have the fan service conundrum. To appeal to the average viewer, a show will put an excessive amount of sexual content, such as 30 seconds of finger sucking (Clockwork Planet), or the traditional falling down and the main character groping the female lead’s chest. There are a significant amount of examples of shows that do this and then have no fan service at all in any of its further episodes. As someone who enjoys fan service when it is not detrimental to the message of the show, this is a case that I use quite often.
If you watch the first episode of an anime and think “Should I watch more of this?” you should think about why you didn’t like the first episode, rather than a binary choice between like and dislike. If it is a problem you can see being due to it only being the first episode, use this rule to make up your mind. In any other case, such as terrible writing, bland character design, or music that makes you want to throw a brick at your screen, one or two more episodes aren’t going to change your opinion about the show enough to continuing further past the 3 episode mark anyway.