It's important to be positive in life.
Being negative all the time is taxing on the mind, body and soul. Your spirit needs light to grow, so walking around constantly in a dark mood stunts your spiritual growth. With that said, surround yourself with positivity: positive people and positive music being a key. If you want to be a happier person, in addition to reading scripture and attending service, you should surround yourself with people who encourage you and support you, and avoid people who tear you down.
Yeah, I know you're probably saying that's common sense. But the same principle works in terms of the music we listen to. Turn your radio dial and you'll find plenty of music tearing down our culture rather than uplifting people, providing an inspirational message. Listen to what you want but if your mood tends to be more melancholy than upbeat, more dark than hopeful, then you're probably surrounding yourself with negative influences that are consciously and subconsciously draining the light out of your soul.
What you'll find in Christian music is a positive, inspirational message that'll give you energy and strength. Regardless of type of music you fancy, the Christian music genre has something for you. Rap, rock, metal, gospel, contemporary, whatever it is you listen to in mainstream music can be found in Christian music. And the message is always positive, always uplifting.