Technically, gratitude journal is an example of selection bias. (A hypothetical impartial observer should make notes about everything, indiscriminately.)
But that's okay, because the purpose of the gratitude journal is not to make impartial observations, but to change yourself. To focus your attention on processes that have proved successful in the past, on resources your have, etc.
This hits on the particular question I failed to ask in this case, which was something like "Is there some particular bias I'd be exploiting for fun/profit/improvement?"
Which, of course, begs the question of whether it is rational to exploit biases instead of trying to mitigate them.
This is the public group rationality diary for November 16-30.
Thanks to cata for starting the Group Rationality Diary posts, and to commenters for participating.
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