Try not to do anything against etiquette

Etiquette to society is what apparel is to the individual. Without apparel men would go in shameful nudity which would surely lead to the corruption of morals; and without etiquette society would be in a pitiable state and the necessary intercourse between its members would be interfered with by needless offences and troubles. If society were a train, the etiquette would be the rails along which only the train could rumble forth; if society were a state coach, the etiquette would be the wheels and axis, on which only the coach could roll forward. The lack of proprieties would make the most intimate friends turn to be the most decided enemies and the friendly or allied countries declare war against each other. We can find many examples in the history of mankind. Therefore I advise you to stand on ceremony before anyone else and to take pains not to do anything against etiquette lest you give offences or make enemies. 
礼仪之于社会犹如衣着之于个人。人若不穿衣服，就会一丝不挂，令人耻笑，必然导致道德败坏，社会要是没有礼仪，就会陷入可悲的境地，而社会成员之间所必需 的交往就会被无谓的冲突和纠纷所干扰。假定社会是一列火车，礼仪就好比轨道，火车只能沿着它隆隆前进。假定社会是一辆贵宾车，礼仪就好比轮子与轴，马车只有靠它们才能滚滚前进。缺了礼节，最亲密的朋友会变成死敌，友好或结盟的国家会兵戎相见。我们可以从人类历史上找到许多这种例子。因此我劝你对于任何人都要讲究礼仪，并且尽力不做违背礼仪的事，以免冒犯他人或者树敌。