Politeness improves our relationship with others; it boosts our confidence and self-esteem improving our communication skills. But being over polite or those who are extraordinarily nice are the one who are likely to stab behind the back than those who are less polite or sometimes even rude.
Politeness is a valuable and social etiquette which defines the personality of the person. It is quite possible that politeness cannot be visualised as rudeness or inconsiderate behaviour which is quite visible when a person is rude. It improves the relationship with others and sometimes complicated situations can be handled with ease due to politeness.