I did some tests on SD 1.5 with certain challenging prompts such as gymnasts doing a handstand. Using no negative prompt they became amorphous blobs. I'm guessing because gymnasts are often in dynamic poses which are hard for SD to understand.
I decided to add a negative prompt. With a bit of experimentation I realised all the "bad" had no effect. However, "blob" actually made most of the deformities go away and "amputee" did help against partial limbs being generated.
Something that worked even better was replacing "gymnast" with "athletic man"/"athletic woman" in the positive prompt.
Welcome to the latent space where you can add, subtract and operate on words like they are mathematical objects. I suppose people are going to intuitively learn how the latent space works by exercising prompts.
I decided to add a negative prompt. With a bit of experimentation I realised all the "bad" had no effect. However, "blob" actually made most of the deformities go away and "amputee" did help against partial limbs being generated.
Something that worked even better was replacing "gymnast" with "athletic man"/"athletic woman" in the positive prompt.