Give me a genre, a location, and something you might do on a date...
As roleplayers, we often think of ourselves as improvisers. My friends at the One Shot Podcast Network (Patreon funding now!) are actually trained in this particular mode of performance, and they have excellent insights into how such training supports their gaming. Part of the fun of improvising, both on stage and in gaming, is the power of making choices in the moment. And because we enjoy this, sometimes we think that more choice is always good, that the freedom to make up whatever we want will let us explode in fountains of creativity. It turns out that this is not the case. And trained improvisers know this very well, which is why so many improv exercises and performances begin with the selection of constraints.
Welcome to roleplaying, where the characters are made up and the dice don't matter.
Constraint is not the opposite of choice. It is merely the practice of having the available choices or parameters for choice presented to the chooser instead of created by the chooser. In the absence of external constraints, we all first narrow our own list of choices before making our final decision. No one considers all possible options equally and chooses from them. Whenever we come too close to doing that, we inevitably suffer analysis paralysis. There are just too many choices for us to consider, and we shut down rather than moving forward. One way or another, we need to make the list more manageable.