Kindness is never worrisome. It will not bring you down. It will not let people abuse you. Do not listen to the world and their saying that "kindness will get you nowhere", or "you'll be taken granted for because of your kindness"; they don't know the real meaning of kindness. They are just lacking it for themselves, so be kind to them too. Be kind to those whom you wish to get back at. Anger won't solve it or make you the more mature one. Be brave enough to be kind. Be balanced enough to be fine. In your words and actions,

Be kind.