It is generally believed that there are two sets of people in life: those who see a glass of water as being half empty and those who see it as being half full. There are also those who will look at a doughnut and see only a delicious treat to be relished, while others will look and only see the hole in the middle. This is just a way of describing the contrast between pessimism and optimism.
Half of the water in the glass may actually be gone, but instead of worrying or complaining over the half that is gone, recognize that the glass is still half full and thereby allow your sub-conscious mind to relay messages of abundance rather than those of scarcity. This helps you to eagerly anticipate the enjoyment of the other half still left in the glass while you believe and work towards replenishing it. Likewise, a doughnut may have a hole at the center, but it still is a yummy doughnut. Go on and enjoy it! On the flip side of a dark and miserable cloud is bright sunshine, which will soon break forth. So despite whatever issues you are facing, you should try to see the brighter side of things and enjoy what life has to offer presently.