Negative prompts work best on concrete, visual nouns: extra fingers, watermark, text, blur. They work badly on abstractions, because "not boring" describes nothing the model can move away from.
They are also over-used. A long inherited negative prompt copied from a forum quietly fights your actual brief. Start empty, add the specific failure you keep seeing, and remove anything that has not earned its place.
QUESTIONS PEOPLE ASK
What should I put in a negative prompt?
The specific artefacts you are actually getting, named as objects. Nothing aspirational, nothing abstract, and nothing you have not personally seen the model produce.