For example, check out this scene taken from The Ren & Stimpy Show (episode "Stimpy's Fan Club") that depicts Ren's torment after serving a full day as President of Stimpy's Fan Club:

While some of this could be depicted using quick and dirty sketches, much of Ren's suffering and various intentions need very specific detail to set the mood of the scene. In some frames, the image alone says far more than any amount of dialogue ever could.
Anyway, the point here is that you should not be afraid to be detailed in your work, but keep it in moderation. If large amounts of detail in a scene isn't going to help the story along much, you should probably keep it simple until it *needs* to become detailed. Allow yourself the flexibility needed to balance your work load, so you only exert the most effort where it's truly necessary.