Upon returning home, the prisoners had to struggle with two fundamental experiences which could also damage their mental health: bitterness and disillusionment. The last stage is bitterness at the lack of responsiveness of the world outside—a "superficiality and lack of feeling...so disgusting that one finally felt like creeping into a hole and neither hearing nor seeing human beings any more" (113). Worse was disillusionment, which was the discovery that suffering does not end, that the longed-for happiness will not come. This was the experience of those who—like Frankl—returned home to discover that no one awaited them. The hope that had sustained them throughout their time in the concentration camp was now gone. Frankl cites this experience as the most difficult to overcome.