People aren't good at being random. when trying to mimic the results of repeatedly flipping a coin and recording heads or tails, people forget that "if a fair coin toss comes up heads thirty times in a row, the next toss is still equally likely to be heads or tails" and this results in people putting down "too many reversals, and too few strings of heads, in their successive guesses" (dixit & nalebuff, 1991, p. 184).