To develop a product, you first have to decide on what product to design and then make a plethora of design decisions in order to bring it to life. What makes your job extra difficult is that you will have multiple forces attempting to persuade you to make these decisions for their sole benefit. You'll feel the temptation to make decisions based on what your competition is doing, what will satisfy your business goals, or what will delight your product's end-user.
Think of yourself as a film director, with your final product being the film you are producing. These prima donnas are present on set, begging to be the star of your film. You must shine the limelight on just one. Your film will be stronger for revolving around one shining hero.
So, which one should be your product's hero?
No, they are other films.
While it can be tempting to one-up your competition, focusing on the competition leads you to build your product off of what has already been created. Making the competition your product's hero would be like riffing off of another film, tweaking it in an attempt to make your version the next blockbuster hit. Your product might be differentiated by a plot twist at best, but won't stand out above the crowd.
"If you attempt to build everything the competition is doing, you won't be building things the competition isn't doing."
-Jon Kolko 
Studying your competition can be quite helpful in determining market gaps and opportunities, but making them your protagonist will significantly limit your product's potential for radical success. Knowing that other films will be showing all around yours in the theater, direct your film to deliver the experience they're not.
The Business Goal?
Nope, that's your sidekick.
Getting warmer! This is kind of a trick question because satisfying your hero's desires will, in turn, accomplish your business goal.
Your business goal states the result of solving the burning business problem that leads you to design a product in the first place. "We need to regain 5% of our target market." or "We need to increase our profit margins by 15%." are two examples of a business goal.
The issue with letting your business goal be the hero of your product is that it gives you tunnel vision. Often taking direct action to remedy the business problem doesn't give you a wide enough lens to see the human behaviors that are driving your business results in the first place. In other words, the business goal doesn't have the superpowers necessary to be a hero.
The business goal is the sidekick to your product's hero. The good news is, when your hero triumphs, so does your sidekick.
Yes! She's your hero.
Since it is your end-user who determines if your product is desirable, we need to design your product upon her desires. We do this by championing her and then evaluating all design decisions from her perspective.
Making your end-user the protagonist centers your product's design on human desires. This opens up the potential to develop a radical innovation  by uncovering opportunities to satisfy unmet human desires. These opportunities aren't confined to the parameters that your competition and business goal have predefined. Therefore, assigning your end-user to the role of hero grants you the largest opportunity at a blockbuster.
Just as Walt Disney would get down on his knees to experience Disney World from a child's perspective, put yourself in your end-user's position to feel what she feels. From her point of view, you can make informed design decisions that fulfill her needs, wants, and desires.
In pursuit of designing a desirable product, your end-user should be the hero, your business goal the sidekick, and your competition merely the other films. Give your end-user her cape and root your design decisions in her desires.
 Kolko, Jon. Well-designed: how to use empathy to create products people love. Harvard Business Review Press, 2014. Print. p. 43.
 Norman, Donald & Verganti, Roberto. (2014). Incremental and Radical Innovation: Design Research vs. Technology and Meaning Change. Design Issues. 30. 78-96. 10.1162/DESI_a_00250.