I once ran a campaign of a game similar to D&D where one of the players had geared a character to be super charismatic and had an end goal of being able to persuade anyone to do anything.

She kept persuading the random side characters that helped them into joining, until they had a small army of Merry Men.

Yeah, the campaign took a back seat while they played Robin hood for awhile.

She started specifically targeting side npcs because I wanted to drop a character that was making my vocal chords hurt. They liked the npc because he was basically a child's vision of a stereotypical pirate.