以下是翻译后的内容： 第八章，“自我优化：完善休闲与身体”，探讨了魏玛德国（1918-1933）的休闲、娱乐以及对身体健康的日益痴迷。首先，它强调了八小时工作/休闲/睡眠制的来之不易的成就，这是劳工运动的关键诉求。然而，雇主们抵制无工作周末的想法，担心工人们不知道如何有效地利用他们的休闲时间，尽管工会辩称这对通过体育和教育恢复工作效率至关重要。 文本突出了中产阶级对工人阶级在道德上如何使用休闲时间的焦虑。它将德国与英国进行了对比，后者据说在休闲时节约能量的艺术更为发达。本章认为，相反，1920年代是一个自我完善的时代。 然后，本章聚焦于柏林的游乐园，如吕内公园，一个“享乐世界博览会”，柏林人可以在那里体验各种各样的娱乐活动，从射击场到现代过山车。尽管吕内公园非常受欢迎，但它也面临着挑战。它代表了战前时代的乐观精神，而现在看来这种精神有些天真。随着社会分层的加剧，不同的阶级开始通过生活方式来区分自己。吸引整个柏林的吕内公园变得不再那么受欢迎。维持如此大型的游乐园需要不断的创新和巨额资金，这让管理者们精疲力竭，并导致了一些游乐园的关闭，比如Ulap。 电影成为了主要的付费休闲活动。20世纪20年代初，看电影从一种混乱、不受监管的体验转变为在宏伟的“电影宫殿”里举行的更有条理的活动。无声电影依靠音乐伴奏来增强情感冲击力。本章指出，无声电影比有声的日常生活更依赖于人类的肢体语言。1927年有声电影的兴起最初遭到了抵制。人们已经习惯了无声电影强烈的身体表现力，不想在电影中听到声音。然而，像由玛琳·黛德丽主演的《蓝天使》（1930）这样的电影，展示了声音在创造一种新的内敛表演方面的潜力，尽管许多无声电影明星很难完成这种转变。 本章还分析了电影《星期天的人们》，这是一部关于一群年轻人在万茨湖岸边一起度过星期天的电影。这部电影充满爱意地展现了简单的生活以及人们希望从闲暇时间获得的东西：一点快乐。 除了娱乐之外，这个时代还出现了健身文化的热潮。电影《力量与美的道路》（1925）展示了健身训练和体操表演，并广受欢迎。锻炼对“完整的人”至关重要的信念跨越了政治分歧，变得普遍。这主要是因为需要抵消城市工作和烟雾弥漫的城市生活方式带来的不健康影响。文本认为，这种对身体的痴迷因第一次世界大战的创伤而加剧，这场战争导致许多人身体受伤。 文本表明，人们对受伤和健康的身体都给予了极大的关注。这种关注很快就进入了哲学领域。 本章接着分析了现代摄影及其呈现身体的新方式。这是一个必须纤细、柔软、反应迅速的时代。 本章还分析了体育运动。文本认为，魏玛共和国时期，体育运动是一项蓬勃发展的产业。 本章还关注了社团，特别是六日赛车，因为它们是许多德国人温暖和生计的来源。这些社团提供了社区归属感。但政治开始在这些社团中发挥作用。 最后，本章分析了极端的军国主义和战斗部队，这些部队是在纯粹的仇恨中建立起来的。

Chapter 8, "Self-Optimization: Perfecting Leisure and the Body," explores leisure, entertainment, and the burgeoning obsession with physical fitness in Weimar Germany (1918-1933). It begins by highlighting the hard-won achievement of an eight-hour workday/leisure/sleep split, a key demand of the labor movement. However, employers resisted the idea of a work-free weekend, fearing workers wouldn't know how to use their leisure productively, despite unions arguing it was vital for restoring performance through sport and education. The text highlights a middle-class anxiety about the moral use of leisure time by the working class. It contrasts Germany with England, where the art of conserving energy during leisure was supposedly more developed. The chapter suggests that, on the contrary, the 1920s were a time of great self-improvement. The chapter then zooms in on amusement parks like Lünepark in Berlin, a "world exposition of enjoyment" where Berliners could experience a wide array of entertainment, from shooting ranges to modern roller coasters. Despite its popularity, Lünepark faced challenges. It represented the optimistic spirit of the pre-war era, which now seemed naive. As social stratification increased, different classes began to segregate themselves by lifestyle. Lünepark, which attracted all of Berlin, became less desirable. Sustaining such large amusement parks required constant innovation and huge sums of money, exhausting managers and leading to the closure of some, like Ulap. Cinema emerged as the dominant paid leisure activity. Moviegoing transformed from a chaotic, unregulated experience in the early 1920s to a more structured event in grand "movie palaces." Silent films relied on musical accompaniment to enhance the emotional impact. The chapter notes how silent film relied on a repertoire of human gesture than in normal everday life with its attendant sounds. The rise of talkies in 1927 initially met resistance. People were so used to the intense physicality of silent film that they didn’t want to experience sound in their films. However, films like "The Blue Angel" (1930), starring Marlene Dietrich, demonstrated the potential of sound to create a new kind of understated performance, even though many silent film stars struggled to make the transition. The chapter also analyses the film "People on Sunday", a film about a group of young people spending a Sunday together on the shore of the Vanzi. The film is a loving look at the simple life and what people hope to get from their free time, a bit of joy. Alongside entertainment, the era saw a surge in fitness culture. The film "Ways to Strength and Beauty" (1925) showcased fitness training and gymnastic displays, becoming wildly popular. The conviction that exercise was essential for a "whole person" became widespread across political divides. This was driven by the need to counteract the unhealthy lifestyles associated with urban work and smoky cities. This obsession with the body, the text argues, was heightened by the trauma of World War I, which left many physically injured. The text shows that there was an intense focus on both injured and healthy bodies. This concern soon made its way into philosophy. The chapter then analyzes modern photography and the new way it presented the body. This was a time where one had to be thin, supple, and quick to react. The chapter also analyses sports. The text argues that sport was a booming business during the Weimar Republic. The chapter then looks at associations, particularly the 6-day race, as they were the source of warmth and sustenance for many Germans. These associations provided community. But politics came to play a part in these associations. Finally, the chapter analyses extreme militarism and combat units, that were created out of sheer hatred.