When you write a scene, try to make sure every character in it, secretly or openly, wants something.
Not all characters have to actually know what they want, but they’ll be way more ‘in’ the scene if they’re hoping for some sort of outcome.
Characters who are ‘unmotivated’ can become passive deadweights – they’re like a shadow cast over the scene. Or worse, they can make the reader suspect the writer has been lazy or forgetful.
So motivate all characters by thinking about what they want from each scene. That way, everyone in your story will seem more alive and real, and so will the scene.