Douglas Adams said this quote
“ The lights were off so that his heads could avoid looking at each other because neither of them was currently a particular engaging sight, nor had they been since he had made the error of looking into his soul.It had indeed been an error.It had been late one night-- of course.It had been a difficult day-- of course.There had been soulful music playing on the ship's sound system-- of course.And he had, of course, been slightly drunk.In other words, all the usual conditions that bring on a bout of soul searching had applied, but it had, nevertheless, clearly been an error. ”