This video about a young woman who suffers from dystonia and can only walk backwards is really interesting, but I offer it up with a sprinkling of disclaimers. 1. It's a clip from the evening news, so naturally it reeks of sensationalism. 2. This shouldn't necessarily discourage you from getting the flu vaccine. 3. Some numbskull tweaked about a second of this video so that it sounds like the reporter is saying this should discourage you from getting the flu vaccine.
If you want to explore some neurological case studies that represent patients as actual people, rather than as tragic spectacles, The Man Who Mistook His Wife for a Hat by Oliver Sacks is a great read.