Whenever raises the topic of an exposition dump or the words are mention I can’t help but be reminded the scene in the opening of Fate Zero where two guys circle a third guy like sharks and talk about nothing for over ten minutes. That scene is by far the worst scene in that anime since not a single piece of information made sense without prior knowledge of the series which raises the question of why this was in the first episode. But enough of that I’m more interested in what makes a good exposition and why there is so many bad ones.
Information is given to us at any moment often without warning and it’s up to the anime to make this process engaging and keep our attention long enough for us to absorb the information. Not an easy task especially if the information in question is dull.
A good example is Psycho Pass which uses crime scenes and distant conflict to communicate ideas, the viewer is interested in crime scene or the upcoming conflict and will stay attentive as the character speak their minds on the way to events or as the crime scene is explored.
A bad example is the most recent episodes of Sasami-san, at first the anime gave us random events without explanation but recently the events have been explained after they occur and those explanations are long winded and often unnecessary to some degree. Sure it’s nice to know how the world works but when your story is based on mysterious random events an explanation is the equivalent of shooting yourself in the foot and then wondering why it hurts to walk.
A good exposition is the type you don’t even notice and those often occur in the episodes filled with action. Shin Sekai Yori presents information constantly but because of the journey the exposition is balanced with action and events which makes you forget it’s there.
I’m certainly no expert and I’m sure you all know of worse cases of exposition dumps, if you can think of a battle in any anime that is more talking then combat then you have witnessed the abomination that is an info dump.