Stoicism and to be stoic are some things that I’ve come across in many situations, but there seems to be a common misconception that creates a lot of problems for people. We are told that “men do not show emotion” and thus that the things certain people perceive as “wrong” about men is that unlike women, men do not outwardly show emotion. This is often referred to as men being “stoic” the calm outside concealing the volcano underneath the surface. This is a misrepresentation of stoicism at its core. However it is a common one in the western world.
The simple definition of stoic from Merriam-Webster is:
a person who accepts what happens without complaining or showing emotion 
However if we look at the full definition of the term, from the same source we get the following definition:
capitalized : a member of a school of philosophy founded by Zeno of Citium about 300 b.c. holding that the wise man should be free from passion, unmoved by joy or grief, and submissive to natural law 
This is a much more accurate definition as the implicit here is control , not absence. If we compare it to a quote by Marcus Aurelius in meditations  the differences start to show up:
“If you are distressed by anything external, the pain is not due to the thing itself, but to your estimate of it; and this you have the power to revoke at any moment.”
Here he states that any emotions that arise from something outside of you, the pain (emotion) is not because of the external but because of your own reaction to it. You have control over your reactions, therefore control of your emotions. This is emphasizing not an absence but a control.
This is further supported by Seneca :
“It is the power of the mind to be unconquerable.”
This is emphasizing the control over the self, not of the external world. The stoics saw that a man should rely on reason, concentration and reflection to transform his emotions so that he could see the world through clear perception and inner calm. The western bastardization confuses the outer calm, with the inner calm, in essence sees calmness as being skin-deep. Which, of course I could draw back to modern western culture being excessively image oriented.
One of the few modern writers that have shown an understanding of Stoicism is the writer Nassim Nicholas Taleb who writes:
“A Stoic is someone who transforms fear into prudence, pain into transformation, mistakes into initiation, and desire into undertaking.”
This is the essence of stoicism, not the absence of emotions but transforming emotions into action, and keeping a clear head while doing so . The three quotes together have 3 major points:
A) Do not let the external dictate your internal state. (Aurelius)
B) Keep control of your inner self. (Seneca)
C) Transform the emotions you feel into action. (Taleb)
The core essence thus, is to be aware of your emotions (so that you can control them) you cannot control that which you are not aware of. Maintain control of your inner self and utilize the capacities for reasoned judgement and self-control to transform inner turmoil to inner calm by engaging in external actions with the internal unrest as fuel.
“When force of circumstance upsets your equanimity, lose no time in recovering your self-control, and do not remain out of tune longer than you can help. Habitual recurrence to the harmony will increase your mastery of it.” Marcus Aurelius – Meditations 
This clearly states that you will lose your composure, but that the importance lays in not only regaining it, but retraining yourself in such a way that you gain mastery in regaining it.
This is echoed by Epictetus when he writes:
“Remember, it is not enough to be hit or insulted to be harmed, you must believe that you are being harmed. If someone succeeds in provoking you, realize that your mind is complicit in the provocation. Which is why it is essential that we not respond impulsively to impressions; take a moment before reacting, and you will find it easier to maintain control.” 
This also introduces perception as a much more central tenet of the philosophy. That by halting reaction and our impulsive natures, we can react more in a manner that strengthens our control and influence on the external. I spoke more extensively on this in my post on how axioms affect perception.
The modern value of stoicism and the connection to the Red Pill philosophy
We live in a society where the external can influence us on a much more broad and constant level than ever before in human history. Where the ancient philosophers may be familiar with conflicts in their own back yard, or arguments with their own neighbors. We are perpetually assaulted by external impressions in the form of 24/7 news broadcasts, websites and social media.
We hear about wars and conflicts in lands that most of us would be unable to place on a map, we are assailed by constant judgment and opinion on what, how and why we should be. This is where stoicism as a philosophy allows you to transform this never before eclipsed rush of sensory impression into action and force.
Perhaps the greatest benefit stoicism can afford to the modern man, is that it allows you to mimic the benefits of the Dark triad outlined by such authors as Kevin Dutton . Once the other party loses control of their emotion, while you remain rational, you have obtained an advantage.
I will leave you with one of the strongest quotes I have ever heard, from one of the great stoics of modern times, Otto Frank.
“There are no walls, no bolts, no locks that anyone can put on your mind.”