Selfishness and anxiety can arguably be rooted in fear. Fear is rooted in attachments. For example, one can be bound to attachments rooted to objects and mental formations that have existed in the past, exist in present, and are expected to exist in the future. This is driven from the ego and its attempt at self preservation.
One can have a present awareness without being attached to what is going on in the present. For example, one can value one’s livelihood, prepare for it for many years, and nurture it for many years, without becoming attached to it. In this way, we do not introduce fear into how earn our rice for the day.
You can treat the wonderful people you have encountered along your journey through the wilderness with loving kindness without being necessarily attached to them. The journey, the people, and the wilderness are all transient. When we remove the fear we make room for compassionate expression.
This may be a reasonable explanation as to why many Buddhist activists have been applauded through the ages for being fearless when fighting oppression, even if it means sacrificing their lives.
It is also a reasonable explanation as to why people are often confounded when the impulses of the practitioner do not align with the impulses of those that surround the practitioner. Sometimes a non impulsive behavior is interpreted as a lack of awareness, a lack of interest etc. However, practitioners have many "gut instincts" that they bring up for vetting because they are aware that many of these instincts are a by product of the ego.
Human beings project their fears and impulses on others. In a way, the projectors witness traces of their own ego in others because they are projecting their fears and impulses and confirming their own delusion.
“Turn the other cheek” is a confounding methodology because it goes against our impulses for the self preservation of the ego. The ego is often in denial about the transient nature of objects, beliefs and other mental formations because of the ego's own transient nature and its attachment to itself.
When we are truly present and aware, we are not bound by such attachments that the ego uses to deny its transient nature and we leave room for compassionate expression.