Emotions are the enemy of reason. Get swept up in emotions and you are bound to lose the goal in your mind. You get swept up in your angst, despair, ecstasy or desire and you are bound to want to act them out, you are bound to start taking steps to fulfill these feelings. Your behaviour, thought-patterns, ideals, goals and dreams will all eventually heavily corrupted in one way or another by an emotion if let it completely overrun you. So, Control your emotions!!!
You should however treasure and cherish your emotions. Many people choose to suppress and hide what they feel due to the effects that such emotions have. Such a reaction could be highly detrimental. Love, Joy and other enthrallments seem to change reason, logic and basic psychological balance; Sadness, anger and fear tend to do something in the same line. Depending on the situation or atmosphere you are in, you might not appreciate the effects. For example, a romantic interest might distract from a given task or anger might get you too steamed up to work properly. You must however remember that emotions are the fuel behind all our actions. You must value this fuel wherever it is from. Cherish your feelings for they might be of use in your future.