We often inadvertently became angry, and you are sentimental, that are some negative emotions. In order not to let negative emotions control us, we have to learn to become the master of emotions. Often smile is a good method.
Remember a word "laugh decade less." Believe everyone is no stranger to this sentence, but at the same time, smile is also a good way to control the negative emotions. When you had trouble with something, might as well smile, when you angry angry because of something, might as well smile, when you are sad because of something, might as well laugh, the things smile can make your mood regulation, make peace deal with things in a better state, in the face of all sorts of things in life.
So, no matter what, remember to smile, because smile contains the infinite magic.