Forget everything you were told as a child; daydreaming is actually good for you.
Research has shown that it: improves working memory; aids relaxation; helps the creation and achievement of goals; and allows complex thought to take place thus facilitating creative problem solving.
It can also instantly make you feel good.
So, close your eyes and transport yourself off to a beautiful place (real or imaginary) in your head. Immerse yourself in all the glorious detail; the sights, the smells, the textures, the feelings. Simply allow your mind to wander.
Now, how easy is that?