Montaigne on having a poor memory:

"Now, the more I distrust my memory, the more confused it becomes. It serves me better by chance encounter; I have to solicit it nonchalantly. For if I press it, it is stunned; and once it has begun to totter, the more I probe it, the more it gets mixed up and embarrassed. It serves me at its own time, not at mine."

—Of Presumption