The siren song of 3D
The biggest barrier between you and your success as a Unity game developer is finishing a project. The idea stage that you enter when you sit staring at that endless 3D plane is crucial to you overcoming that barrier. If you choose the right idea, you will have a much better shot at finishing. Choose the wrong idea, and you might crash and burn. Then you'll probably go back to school and study to be an accountant. Starting in game development and ending in accounting is your worst-case scenario. Let's avoid that at all costs.
Before you even begin, the odds are stacked against you. That endless 3D plane is calling you, begging you to start a project that's way over your head. You may begin thinking of the other 3D games you've played: gritty, wide-open "sandbox" games like Saints Row or Grand Theft Auto; tightly-controlled platformer games with lots of exploration and interesting challenges like Super Mario 64; sweeping, epic role-playing games like Skyrim or Fallout...