@thor (1/2) Simply put, if you type "anime girl" in the prompt, the diffusion model will generate something, anything, that could fit the "anime girl" tag, that may include missing limbs or deformities. Because of this, you could either add "cute" in the prompt or "zombie" in the negative prompt and it will try to generate something that fits those characteristics.
With that been said, blindly adding negative prompts will backfire, let's say you put in the prompt "2 hands" and...
@thor (2/2) In the negative prompt "more than 2 hands", the model will find it hard to generate good hands, since it is both being instructed to generate hands (2) and to not generate hands, and pictures with 2 hands and pictures with more than 2 hands share way too many similarities (the presence of hands). This will result in an increased rate of deformities in the hands. To properly add negative prompt is best to keep things short and precise, or use embeddings.
