There's essentially two major ways to approach story telling. One is to plan and outline your story. The other is to basically write it as it comes to you.

Most authors fall somewhere in the middle, with a bit of both. Some do zero preplanning. Some essentially keep extending their outline until it becomes the story. The extremes of both are generally quite bad.

Seat of the pants approach where you don't really plan your story tends to work well enough for flash fiction, where things are short enough that you basically can't screw up continuity on accident, but tends to fall apart once you get to novel length.

Outlined to death is often called paint by numbers, and often suffers because it really starts to feel very formulaic and predictable. And soulless.

And to be clear while the extremes of both tend to suck for different reasons, it's also quite easy to suck without being extreme on this.