We live in a world that sells the selfish illusion that life is about "being happy". Do what makes you happy, live however makes you happy, etc... All we do is sell a lie that I can do what I want, say what I want, act how I want, and live how I want as long as I'm happy and it doesn't matter who I hurt, who I take advantage of, who I wrong, or who I offend as long as "I'm Happy!".
The problem with happiness is it is an emotion/feeling and the problem with emotions/feelings is that they come and go, are based on our circumstances, and they aren't always accurate. They also can be very selfish, self-centered, and justify behavior, attitudes, actions, and lifestyle choices which lead to bigger problems.
You see, when you live only for "YOUR" happiness then you life is good as long as you get your way, get what you want, things go the way you plan them, and you are in control. However, that is a miserable way to live because you will spend more of your time unhappy than you will happy because you will create constant negativity, drama, turmoil, bitterness, anger, and a rollercoaster of emotions because you are living in a fantasy world and your world will be turned upside down every time you are NOT HAPPY!
You will blame others, make others miserable, and push people away when you are unhappy, and in your pursuit of being happy you will do the same thing because you think your life is about you being happy all the time, not considering the consequences, condition, and outcomes of living with this type of mentality.
God is our creator and He created us specifically to have a relationship with Him. He also created us to have a relationship with Him based on His structure, boundaries, and guidelines not ours. While God did not create us to be unhappy, He did create us with an understanding that we will be happy sometimes, but sometimes we won't. Because life the way God meant it wasn't meant for our happiness, but for His pleasure.
God understands that happiness is temporary and is based on circumstances that come and go with our feelings/emotions, so it's unrealistic to think we'll be happy all the time. Secondly, His desire is for us to live in a relationship with Him, which causes us to be unselfish and think of others first, and more importantly striving to live for God first in our lives. That doesn't mean we neglect ourselves or we live unhappy lives, it simply means our lives aren't ruled or dictated by the selfishness of seeking only our happiness.
Truly God created us to have Joy not happiness. While God I am sure wants us to have plenty of happy moments, He wants us to truly have Joy. Joy is an attitude and a lifestyle choice and not an emotion/feeling. We can still have Joy even when we aren't happy. But it all depends on what/who we are living for?
Our world today is filled with people who only care about being happy, it doesn't matter if it goes against what the Bible teaches, it doesn't care if it hurts anyone, or has long-term side effects for others, and most of all the don't really care what God thinks, or even worse they still try to hold some sort of religious or spiritual stance trying to say God wants us to be happy and if living this way or doing this makes me happy God is ok with it, and the truth is you or I or know one has the authority to speak on God's behalf. God is not divided, and God doesn't change, and if we want to know what God feels on a subject we go to His Word and we can twist it, try to manipulate it, and change it to fit our sin or selfish behavior, but at the end of the day, that is no way to live because it won't last.
My encouragement for you is to stop trying to "Be Happy" and start trying to live a life of Joy.
Stop pursuing things that you think make you "happy" and start seeking God to help you discover things He has for you that will give you "Joy". Instead of trying to make everything about you and your way and your control so you can be happy all the time, realize what I've been saying is true about happiness and instead surrender your will to God and make it about Him and His Way and giving Him control of your life so you can experience true Joy.
Those who only live life in this world for their own happiness will never find true peace, purpose, contentment, and meaning, but those who give up on selfish and worldly happiness and seek JOY instead will realize that Joy is eternal and will give their lives meaning, value, purpose, contentment, and peace that will only be found in a true relationship with God living by His standards, His spirit, His Word, and His truth.
So instead of don't worry be happy, don't worry and find Joy. Stop living for the illusion of happiness and start seeking a Joy that comes from God and not you.
Romans 15:13 (NIV)
13 May the God of hope fill you with all joy and peace as you trust in him, so that you may overflow with hope by the power of the Holy Spirit.