Being kind isn't really hard to do. Rather it is one of the easiest and liberating things you can ever experience. Just compliment someone or pick something if they have dropped and viola! you just did a kind gesture. Being kind doesn't only give happiness to others but also to the person who is being kind.
A single act of kindness throws out roots in all directions, and the roots spring up and make new trees.
And according to me, being kind is kinda selfish. Let me explain, just like you think that if you do something bad then it will come to you back in some of the other ways or simply called as bad karma exists. Then why do we forget that in the world good karma also exists? So, if you do something good for someone else it will come to you in some or other way. So, if you are helping someone or just being kind then one day when you are in desperate need you will encounter someone who will help you out. So, by helping someone now you are actually helping your future self. In short, being kind is kinda selfish.
Other than this also we should just be kind. You never know what the other person is going through or what battles they are fighting.
Some people just don't like telling others about their demons. It's not because they are self-absorbed or arrogant. They are just built like that. They would rather go through that alone than to burden someone with their mess. And so, in this situation, the only thing you can do is to be kind.
Degrading or putting someone down doesn't raise you up or puts you above them. Calling someone fat doesn't make you skinny, calling someone stupid doesn't make you smart, calling someone boring doesn't make you cool. You see, our generation is so busy in being cold, savage and heartless that they have forgotten what it is like to be kind, humble and loving. Your one word can get stuck in their mind for the whole life. That one word can change someone's whole perspective or outlook on life. So it's better if it's a kind word. Because you never really know how you changing someone life. Every person in this world is different with different qualities so if you don't get along with some don't force them, just stay away from them and let them live their life. Instead, be kind and create a safe space where they can be themselves. Be so yourself that others feel free to be themselves too.
Be kind to yourself too. Be humble. Treat others and yourself with respect.