the.com/side quest
the plot you weren't supposed to follow, which is somehow the whole reason you kept playing.
means an optional detour from the main goal that turns out to matter more than the goal did.
from born in tabletop and video game design, where the main quest is the story the designers want you to finish and the side quest is the story you find by ignoring them.
gaming termpopularized by rpgs like final fantasy and skyrim
life usagenow means any glorious unplanned detour, irl
design secretoften has better writing than the main plot
for instance
skyrim's paarthurnax — a dragon side quest that outshines the main storyline entirely
the witcher 3 gwent — a card game detour players spent hundreds of hours on
real life airport layover — turns into a spontaneous 14-hour city tour, no regrets