Is having mastery over one’s mind, essentially the same as having mastery over one’s own emotions? And if not, what is the difference between the two forms of mastery?

In a sense, this is a true dichotomy because the mind is truly divided. It has multiple layers in fact, but three primary ones. The conscious level of the intellect is where you do ruminations, you do strategic thinking and planning, you do the work to bring forth many threads and combine them into a new tapestry to launch a creative endeavor of some kind, whether in the arts, a field of scholarship or research, or something more immediately practical as in running a business and solving a knotty problem in a production line or a supply line shortfall or scheduling complexities. Everything the conscious mind does depends on the lower levels of consciousness, the subconscious realm, so this is not a case where the levels of the mind always work independently of one another until purposely called on and with an awareness this is happening. It is very much the case that as the higher conscious level thinks its thoughts and wants to recall facts and figures, prior plans and obligations, and so forth, the subconscious will follow its lead and retrieve from long-term memory the information needed for the conscious mind to do its work, and this will be floated up from within and appear within the conscious thoughts of the person without an appreciation where the information truly comes from and how it is retrieved. It will simply happen, and often with rapidity, and it will seem as though everything is just lying there in the open and can simply be picked up and used rather than there being a very elegant and complex series of steps that must take place. It is indeed designed to be speedy and highly efficient. That is an aspect of intelligence after all, and has tremendous survival value. When faced with a new threat there must be an immediate recognition and reaction based on prior knowledge of the nature of the threat, and the implications, and the various defensive strategies that might need to be brought to bear in order to survive the encounter. Speed is of the essence in such circumstances. It is no less true than when in competition, as in business, when there must be important decisions made, sometimes on a daily basis, that will determine tangible outcomes and overall will govern the success or failure of the endeavor. So, much is at stake and there must be an ability to function with speed and accuracy both to not make grievous mistakes that might not allow a satisfactory recovery if they become too costly. So the levels of the mind work in tandem and seamlessly with respect to the conscious level and the upper subconscious that will retrieve the long-term memories from storage that are needed. The deep subconscious is another matter. This level of the mind is highly segregated and functions on its own and is independent. It is still connected to the soul but it is not connected to the conscious mind and its thinking in a way that it can communicate directly and share its thinking. It perceives what is taking place at the conscious level but it is not able to provide thoughts directly that the conscious level can perceive, as in a dialogue, and share those thoughts. This leaves only the emotional realm as a means of communication. The deep subconscious is connected quite intimately with the levers governing emotion and can trigger any array of emotional experiences and consequences it deems appropriate for what it is experiencing. When it is in a state of alarm it can cause almost anything to happen including sheer panic and a state of overwhelm that can incapacitate a person while, at the same time, the individual will have no conscious awareness why it is happening. It will be entirely inexplicable. So this is a highly undesirable state of affairs and complicates the ability to be in control of oneself, let alone work optimally, using all of one’s faculties.