I have just started learning game/graphics programming (with OpenGL) for a few days. Everything I know so far is very radical like camera, VBO, shader concepts,...Im just very curious to know what banal challenges/problems in game programming are to kinda guess the time I will need to dedicate to my learning. My biggest perfection at the moment is to make a pure looking 3d game with many open worlds and pretty looking shaders.
What are the challenges that I should be afraid of (or prepared for) the most to make that kind of game?