Emotion is determined in large part by thinking. Thinking causes the release of certain chemicals in the brain. There is always a slight lag between a change in thinking and a change in feeling. This is because it takes time for the balance of these chemicals to change in a degree significant enough to alter our mood. The good news about this lag is that it gives us time to change our pattern of thinking before the negative emotion sets in. In a sense this is how modern antidepressants work. They change the rate of resorption of some of these chemicals. We always want to “feel better right now”. Well, give it time.
One other thing, people need to stop equating feeling “happy” with enlightenment. Dukkha, suffering, does not equate to “I feel bad”. It is far more complex than that. Our emotions serve a purpose. They tell us where we stand in relation to the external world and if we need to change something. They spur us to action and keep us out of harm’s way. Just as the burning feeling you feel when you stick your finger in a candle flame tells you to remove that finger or you will be damaged. Some discomfort and even some fear or sadness are necessary for our daily existence. This said, meditation, just in and of itself, does add to our happiness and decrease fear and sadness.
I suggest that those who have not already done so, spend some time learning the meaning of the Four Noble Truths. Understanding dukkha on an intellectual level at first may prove useful for the beginning student