Emotion

“When a man is prey to his emotions, he is not his own master.” 

~ Baruch Spinoza, Ethics

More on Emotion:

“I don’t want to be at the mercy of my emotions. I want to use them, to enjoy them, and to dominate them.”
 ― Oscar Wilde, The Picture of Dorian Gray

“I think of myself as an intelligent, sensitive human being with the soul of a clown which always forces me to blow it at the most important moments.” 
― Jim Morrison

“In order to move on, you must understand why you felt what you did and why you no longer need to feel it.” 
― Mitch Albom, The Five People You Meet in Heaven

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Emotion     /əˈmōSH(ə)n/

noun
a natural instinctive state of mind deriving from one’s circumstances, mood or relationships with others.

instinctive or intuitive feeling as distinguished from reasoning or knowledge.