Still, I don't regret brainstorming or writing scenes with unnecessary dialogue. If anything, thinking about and writing those scenes helped me grow my character and practice my editing skills. Realizing that those types of scenes were unnecessary and a.) learning how to make the scene/dialogue relevant or b.) cutting the scene, helped me become a better writer and editor.
So, don't worry about writing unnecessary dialogue. Write it anyway, if you realize it doesn't work later, scrap it!
What's the best scene you've ever cut from your novel or short story? Tell me in the comments!