Good communication skills, adaptability & variability and a strong mind are the keys that can enable one to attain success in every sphere of life. Planet Mercury is the god of the powers of communication, interpretation, self-expression, intelligence and reason. So, a person enjoys the most beneficial results in the above areas when Mercury plays a favorable Role by it's transit. However, we face hurdles and obstacles in the proper enjoyment of these areas of our life when transit of mercury is weak or unfavorable with respect to our chart. 

Mercury is the ruler of our thoughts and the constant activity that goes on in our minds. As it represents your capacity to understand the desires of your own will and to translate those desires into action. The position of Mercury in an individual's birth chart makes the complete difference and decides his/her level of success in life. But a weak or unfavorable transit of Mercury can give rise to lack of concentration, restlessness, nervous disorders and eccentric behavior, personal misunderstandings, flawed, disrupted or delayed communications, negotiations and trade.