If one is calm and collected, we can make informed decisions. These decisions that we make are based on our experiences and our intuition. What we tend to do is always react, we make issues bigger than that they actually are.
If we stay calm, we are able to see the broader picture and this means that the approach that we take will encompass all perspectives. When we understand each perspective, we are able to take that action, which will benefit not only yourself but others too.
When we broaden our vision from the single perspective to a whole perspective that covers humanity, we end up being more selfless.