@tante Nietzsche's early essay on The Uses and Disadvantages of History for Life gives this subject a great treatment:

"All acting requires forgetting, as not only light but also darkness is required for life by all organisms. A man who wanted to feel everything historically would resemble someone forced to refrain from sleeping, or an animal expected to live only from ruminating and ever repeated ruminating. So: it is possible to live with almost no memories, even to live happily as the animal shows; but without forgetting it is quite impossible to live at all. Or, to say it more simply yet: there is a degree of insomnia, of rumination, of historical sense which injures every living thing and finally destroys it, be it a man, a people or a culture."