Comments by "T J" (@TJ-hs1qm) on "" video.

Politeness is a product of power imbalance, and it works for those in power. Asking politely for a pay raise isn't likely to achieve much. However, if your landlord politely informs you that the rent is going to double, or if your boss asks you politely to finish the work over the weekend, you feel the threat. Hence, you do what you've been 'politely asked' to do. Anyone who has to endure this on a daily basis resorts to sarcasm to get along. Among family and friends, politeness and sarcasm are much less useful. I guess, politeness and sarcasm are the result of centuries of refined social and economic class hierachies. It is also how lower classes mimic the language of people in power, either to avoid open confrontation or to use etiquette to appear morally (but not factual) equal. The greater the class differences, the more politeness you'll probably see.
1