A Living Hell
Remember Geordi La Forge’s VISOR (Visual Instrument and Sensory Organ Replacement)? Well, it was actually based on a hair clip. LaVar Burton described wearing that VISOR as a “living hell” as it gave him headaches and also reduced his vision.
Source: Ex Astris Scientia
Random fact: Shatner claimed that his favorite episode is “The Devil in the Dark” because he says it had all the elements that made ‘Star Trek’ successful – intelligence and excitement.