It was especially irritating to Nadia because she herself was in such a good mood. She saw no reason to quarrel, and it disturbed her that the others didn't feel the same. Why did the dynamics of the group fluctuate so? Here they were on Mars, where the seasons were twice as long as Earth's, and every day was forty minutes longer: why couldn't people just relax? Nadia had a sense there was time for things even though she was always busy, and the extra thirty-nine and a half minutes per day was probably the most important component of this feeling; human circadian biorhythms had been set over millions of years of evolution, and now suddenly to have extra minutes of day and night, day after day, night after night - no doubt it had its effects.