They are part of the Clauses thingy
The development, the happening, the incident, the occurrence, the situation. The affair, the encounter, the meeting, the moment. the episode, the problem and solution. Others have mentioned these or their ilk: the chapter, the passage, the story, the period, the attack, the bout, the installment, the phase.
A lightbulb appearing above someone's head meaning “I have a great idea” is because, A) a bright image like a lightbulb is a metaphor of a bright idea, a good and smart idea. ... So when someone has a bright idea, they're having an Edison moment, like Edison's bright idea of the bright lightbulb.
Answer:
I feel like it's a because that's what works for me
