There is a Richard Feynman documentary I saw where he talked about his darkest episode of depression (another depression episode). It was after them testing on

There is a Richard Feynman documentary I saw where he talked about his darkest episode of depression (another depression episode). It was after them testing one of the Atomic bombs when it had been developed. He described it as follows, he would for example watch see someone building a bridge or doing maintainance, and he would think to himself, "Why is he doing this? Doesn't he know that he is wasting his time, that all this work he is doing is useless?"