Talk less but, say more
Words once spoken cannot be taken back, so be careful about what you say and how you say it.
The written/said word has a lot of powers. It can spoil your relationship with your colleagues, it can upset families. It can put people in embarrassing positions & situations.
When others misbehavior with yours or fail to give respect, do not get disturbed, don't get angry or sad. Try to find out why they did so. Reduce your expectations from them.
Courtesy is just like water, it cools the ill-tempered person.
Politeness/Courtesy behaving always raises the dignity and honor of the person who come in contact with the day today life of the society.