According to Thor Heyerdahl, it is almost impossible grasp the meaning of time. He didn't believe it exists and he felt this again and again, when alone and out in nature. As Henry Ford said, it feels at such moments that "life is just one damn thing after another". Nevertheless, in the BBC’s The Wonders of the Universe, Brian Cox argued that, thanks to the second law of thermodynamics, entropy means that does indeed flow, and in only one direction.
See also: Halcyon's Time archive.