A jury is more likely to be sympathetic to your claim if they believe you are presenting an accurate picture of the accident and not exaggerating your injuries. Objective injuries can be verified in a way other than the client's complaints. For example, a broken leg can be verified by an x-ray. The jury can be shown the x-ray and see the fracture themselves. In these cases, the jury will generally believe that an injury exists.
Many injuries arising from auto accidents are subjective.
It is difficult to objectively verify these injuries since muscle strains or sprains cannot be seen on x-ray. A jury or a panel of arbiters might feel that an injury is exaggerated when there are no objective findings to support the injured person's complaints. This is not to say that the plaintiff is not injured, as muscular injuries can be very troublesome and long lasting. However, the plaintiff always runs the risk that a jury may not believe that an injury exists or that it is less severe than the client describes. Another factor may be whether your doctor prescribes medications.