Fatigue: The subconscious mind of man is extremely active and since in the process of its work it consumes energy, in due course of time it naturally produces a feeling of fatigue and depression. Nervous fatigue can also result in the subconscious is extremely tired due to mental conflict. 4. Boredom: Boredom and fatigue are not identical. Fatigue is the result of the use of energy but boredom is the feeling of tiredness due to an incomplete or improper expulsion of energy. If you go to a friend and he is busy in some work you become bored. Similarly, you get bored if a person persist in talking about the same thing day after. Boredom result in restlessness, a state induced by our inability to find proper use for our capacity for work.