Pathological nostalgia: always indulging in the memory of the past, tirelessly repeating the past and the environment and conditions of the past. Which of the following are not pathological nostalgia? ['After Zhang changed his new unit, he always complained about the status quo and always said how good the original unit was.', 'Attaching to past experiences, placing too much emphasis on past achievements, and keeping the certificates, medals, and awards obtained perfectly, and often recalling the glorious experience of that year.', 'Attaching to past friends, making new friends, and expanding personal relationships.', 'Alone in a different country as a different visitor.']