Being polite is a worthwhile pursuit. Being kind is considered a synonymous behavior. The subtle difference between the two should not be ignored.
In most situations there is little to note. Being friendly to your grocery bagger, neighbor, or coworker is a good thing. Being respectful to those you meet as you go about your day is a good thing.
It is at times of pain where kindness becomes much more difficult than politeness.
Being polite in the face of conflict is pretty simple. Use nice words. Be civil. Say things that are accepting of alternative viewpoints. Tell people you hear what they are suggesting. Politeness only requires you to say these things. It requires no alteration in how you process other viewpoints. It requires no sacrifice of yourself.
Reacting to disagreement with kindness is an altogether different activity. Kindness requires generosity, not just words. Generosity requires giving of yourself, usually in the form of your time and actions. You cannot react kindly to someone disagreeing with you without also talking with them, helping them, or coming over a bit to their way of thinking.
How did you react during past arguments? Did you spend most of your time defending your opinion with civil language? Did you spend the remainder of your time on the topic silently stewing or complaining to like-minded individuals?
The power of kindness over politeness does not only apply to pain you are caught up in. Kindness considers the pain others are feeling. When a friend tells you a tree fell in their yard and they will be cleaning up for a week, do you say, “Let me know if you need any help?” Or do you say, “I want to help, can I come over tomorrow morning?”
Kindness comes over.