We go through a roller coaster of emotions every day. Our moods are constantly changing from time to time. We could be both happy and sad for no reason. At times we could look in the mirror and say darn I look good today, others days you could feel discontent about how you look. Some days we hate the life we are living, other days you feel lucky to have the life you have. Before I thought you could control your emotions, but I’m starting to realize that emotions arise subjectively without you making a conscious effort.
Let say someone insulted you and you feel your blood pressure rise. For a minute, as your body floods with resentment, your chance of staying calm is slim. You take a deep breath. Turning away expressionless, you muster all the spiritual benevolence you can, and for once you don't counter-attack. You say something impressively forgiving and dignified.
Hard do you eh, I guess it just comes down to how you interpret and respond to the situation, your emotions control you when you assume there's only one way to react, but you always have a choice. Make the right one.
Sometimes though its due to the negative core beliefs about oneself. There are people who think of themselves not highly enough. Their self-esteem is essentially in the gutter, and their emotions are the result of not being able to love themselves adequately.
Sometimes you just have to change your perspective on life.