Philosophers agree that regret is one of the most intense emotions we feel, but they have argued about whether it is productive or useful. Nietzsche said that remorse was “adding to the first act of stupidity a second.” Thoreau, on the other hand, praised the power of regret: “Make the most of your regrets; never smother your sorrow, but tend and cherish it till it comes to have a separate and integral interest. To regret deeply is to live afresh.”
