This sentence uses a modal verb 'should' to express guidance and recommendation.
Meditations
Author: Marcus Aurelius
Douban Rating: 8.2
Yilin Press
The life philosophy of a Roman Emperor
1. Never attempt to guess what others are thinking; those who dwell on the thoughts of others are rarely happy. Everyone should focus on their own inner world; to fail even at this is truly lamentable.
2. The so-called lucky person is the one who creates luck for themselves; luck is a virtuous tendency of the soul, good motives, and noble actions.
3. The closer a person is to tranquility, the more powerful they become. Sorrow and anger are both forms of weakness; both can cause injury and even lead to mental collapse.
《沉思录》
作者：玛克斯·奥勒留
豆瓣评分：8.2
译林出版社
古罗马皇帝的人生哲学
1. 绝不要试图揣测他人的心思，过度纠结于他人的想法的人往往难以获得幸福。每个人都应专注于自我的内心世界，若连这一点都无法做到，实属悲哀。
2. 所谓幸运的人，是能够为自己创造幸运的人；所谓幸运，乃是灵魂向善的趋向、良好的动机以及高尚的行为。
3. 一个人的内心越趋于宁静，便越显得强大。悲哀与愤怒皆是脆弱的表现，两者都会使人受挫，甚至导致精神崩溃。