Fiesta 95 was a holiday planet. The Sixth Doctor, having recently regenerated, planned to go there while in a very delirious state caused by post-regenerative trauma. He soon suffered violent mood swings which escalated in an attempt to kill his companion, Peri. Unable to remember this when the dementia subsided, he changed his mind and decided to go to Titan III instead. Still not thinking clearly, he sought to punish himself for attacking Peri through self-imposed exile as a hermit. (TV: The Twin Dilemma)