Some say there is one god, others say there are many gods, and others say there is no god. Still, there are others of us that rightly claim there is one true God with our minds and yet we claim there are many gods with our hearts. Allow me to explain.
As John Calvin said, our hearts are idol factories. In other words they manufacture gods. Our hearts are naturally bent towards fashioning things on a daily basis that we depend on to supply us with what only God can ultimately provide. Unfortunately they aren't always easy to spot either. We can deceive ourselves pretty easily.
Occasionally when I am upset about something, I have been able to discern that it is because I am placing too much stock in something, or someone, to provide happiness for me. This doesn't mean that you can't ever be anything but happy (since that idea alone would steal your joy by expecting what is impossible in a fallen world). The hard part about this is it takes reflection. It requires people living in the world of countless entertainment opportunities and millions of things vying for our attention to slow down long enough to ask and answer the question, "Why am I feeling this way?" You might not always unveil something that you have elevated to the status of god but many times you will.
For example, when you pry at your heart you might sense that you are frustrated because a person did not fulfill your needs. Next you can ask, "Am I expecting them to be perfect?" If the answer is yes, then you have selected a bad god that can't provide for you perfectly like God can.
Perhaps you might discover that you are angry that you can't stay healthy. You take care of yourself as well as you possibly can by eating healthy and exercising. Yet you still find yourself struggling with illnesses or injuries. But a healthy body cannot provide to you the lasting joy that only God can. If this is the case, then you have selected a bad god. Your health can be taken from you at any moment. Why worship that which is not dependable?
It could be that you desperately want to succeed at work, have a consuming passion to be rich, have an overbearing focus on your kids, or want to be famous. All of these things (health, success, money, influence, parenting, relationships) can be great blessings. The problem comes when they are elevated to a tier in which they were never intended to sit upon. Often we don't know that we have lifted them up on the shelf until God has smashed it off the shelf and we are left to deal with our god being demolished.
I understand that life is not easy and that life is not so simplistic and formulaic that if you can simply keep God in his rightful place then everything will go smoothly for you. In fact, in that case, your god could be comfort or an easy life. Admittedly, the discovery alone is not going to automatically bring joy in the short-term. Nevertheless, it does help to know that you are expecting someone or something to deliver something to you that they cannot deliver. A good place to start is repenting of worshiping false gods and adjusting our expectations.
As the Holy Spirit tells us through Paul, "For there is one God, and there is one mediator between God and men, the man Christ Jesus, who gave himself as a ransom for all, which is the testimony given at the proper time" (1 Timothy 2:5, 6).
1) One God. How many gods does Paul say there are? He says there is one God, and if there is one God then all of the others are fake. They lie when they promise what they can't deliver, and Satan himself loves to make those other gods appear like chocolate chip cookies with rat poison inside. The cookie looks good so we ingest it. Then we discover that it is actually going to kill us.
2) One Mediator. Paul also claims that there is one mediator--Christ Jesus. The word translated mediator indicates one who intervenes or bridges the two parties that he refers to: God and men. Therefore your accomplishments, successes, relationships, parenting ability, physical health, or anything else will not mediate for you. If you think that there is any level of accomplishment that you can obtain that will impress God to the point where Jesus is unnecessary as a mediator then you are kidding yourself. There is simply nothing that you can do to impress God at this point. Only one perfect human could intervene between us and God.
Again, not all disappointments can be traced back to misplaced worship. But if your heart is an idol factory, and you know that it is, then don't ignore what your disappointments and discouragements want you to see--there is one God and one mediator.