Nostalgia may be psychologically beneficial but it can also be harmful (“Bringing on back the good times”, June 22). One form of harmful nostalgia is exemplified by the Trumpist slogan “Make America great again” and the Brexit slogan “Take back control”.

This “good old days” nostalgia is harmful and, I believe, pernicious, because its proponents forget, or fail to recognise, that their “good old days” were probably bad old days for many, if not most, other people. In addition, it is pointless because conditions in the “good old days” were so different from present-day conditions that it would be impossible, or indeed dangerous and undesirable, to attempt to reinstate these conditions.

Another form of harmful nostalgia is suffered by those whose reflections on their past life are dominated by regret, remorse or anger about

previous actions which they or another person did or did not do. According to some definitions of nostalgia, such persons are not nostalgic, because they do not have “a fond remembrance of an earlier time in their life”. But they do have a desire to return to that earlier time, albeit one that is no less pointless or pernicious than that other