I've been interested in programming for a while now, and have been slowly, slowly, slowly working on things over the years. However, I don't feel like I've learned much.
I've only really stuck with familiar languages (Java, C# and I've tried a little bit of PHP). The problem is that in those languages, I've only brushed upon the surface of them and have restricted myself to doing fairly simple things.
For example, as a Java project, I've downloaded the source code for some game and changed a few things to my liking, but nothing terribly difficult. In C#, I've made a few WinForm and console projects to do some repetitious or routine tasks for me, which is nice, but again nothing too complicated.
I've just barely begun to grasp the concept of classes, multithreading and some basic but essential tools that are required in modern object-oriented programming. ("Why can't I just shove everything into one monster-sized class?" "Why can't I just run everything in one thread?" are questions I used to wonder about)
I've never made a large project by myself. Ultimately, my kind of "dream" hobby project is that I would like to create a game using DirectX technology. I say that because I've used XNA but it requires the user to install a framework to get it running, and I also feel that if I use the framework, that a lot of the back-end work is being obscured from me. (DirectX or OpenGL seem to be about as close to the machine as I can get without going overboard in complexity. DirectX is also installed on most [if not all] Windows machines that plan on running games.)
But I haven't even begun to even think about starting that. The amount of things I need to know to undertake a task is absolutely overwhelming. I wouldn't know where to begin. Likewise, I also feel inadequate because I've restricted myself to [what I see as] easy languages. I feel like I should start learning some scripting language or learn this or learn that, which is quite daunting.
tl;dr: I've been slowly teaching myself to program for a while now, but have been restricting my knowledge to limited languages and only scratching the surface of what I can do. I want to learn more and possibly start a decent-sized project (I can only make so many text-based RPGs and calculators), but the massive amount of knowledge I'll need is very intimidating.
One of my concerns is that I know so little about programming languages in general. Is it better to learn several languages or to be able to delve deep into one single language?
How can I motivate myself to learn more?
Am I thinking about this the wrong way?