Emotions are hard for everyone to learn about, understand and even more difficult to control. Even adults have a hard time. This is why it is so important that we introduce the different emotions early to let children be aware of them. There are many activities that help with this.
The first rule of thumb is to point out the emotion when they are feeling it. If they are happy or sad, ask them if they are happy or sad. Digging a little deeper, activities such as these can help children learn important concepts and be able to decipher between the different emotions.
Not only is it helpful for their future as they grow, but understanding emotions can help normalize them. No one should feel embarrassed for emotions they have, and the earlier children learn this, the better it is for them. Working through powerful emotions can help children be the best person they can be.