Even though we can prove negligence in the sense that it was a failure to meet a standard of care, and an injury was caused by that negligence, we must often deal with the law of contributory negligence.
This means that if you were partly to blame for your injuries, your money damages would be reduced in proportion to your degree of fault.
In automobile cases, a version of this is often called the “seat belt defence”, and the legislature has decreed that if you are injured while not wearing a seat belt, the insurance company can reduce your damages by 25%, whether the failure to wear the seat belt contributed to your injuries or not. In all other accident situations, the defendant has to prove that you did not take reasonable care for your own safety, and that your conduct contributed to your injury. The court then apportions fault in percentage terms, such as 60/40 or 80/20.