Sometimes an actor does such a good job with a small roll that the writers can’t help but make it a reoccurring roll. Or even a feature.
Saul on Breaking Bad
Ben on Lost
Toby on The Office
The writers weren’t planning on making these roles full time roles but after seeing the actors’ brilliance and energy, they had to keep writing them into the story.
And we have the same choice. The stuff that we weren’t planning on being the main thing suddenly has a spark…and it’s up to us if we want to write more of that spark into our story.