Why do some people like difficult programming languages such as C++ and Haskell? Here's my theory...

That's probably pretty on-the-mark.

I know that for me, most of the appeal of Haskell is that every new language feature I learn is something mind-expanding. It's not just that it's difficult, though - it's that it's conceptually mindblowing, where each concept is widely applicable to a bunch of different programming situations. And it doesn't do anything like other languages, so you have that feeling of clawing your way up the learning curve and exercising your brain at every step.

I know a decent amount of C++ too, but not enough to be an expert at it. In my view, life's too short to get good at C++. It feels like when I learn a new C++ feature, it was bolted on to solve somebody's particular problem, and isn't conceptually educational like Haskell.

And I did end finding (well, making) a more rewarding job, and am perfectly happy using Python & JavaScript for it, but it remains to be seen whether this "job" will ever make any money. There's a set of hard problems, and a set of problems people will pay you to solve, and fairly little overlap between the two of them. If you're in the overlap (like Google), good for you. However, even in a startup, about 95% of the work is dealing with nitty-gritty details that really aren't that difficult or exciting. (The remaining 5% is what makes you rich, but you can't ignore the boring 95% without having all your customers ignore you.)

People enjoy programming in C++?

Many people enjoy learning difficult things for the challenge of it, but no sane person enjoys using tools that remain difficult once understood. There are concepts in Haskell (and Lisp, ML, Smalltalk, etc...) that are considered difficult or confusing by the mainstream. They're also powerful, making it rewarding to learn them. Languages like C++ and Java are difficult simply because they're big and inconsistent - memorizing them is not very rewarding.

Alright I admit it, I'm one of these crazy people. I've been programming in C/C++ since junior high. It was the second language I learned (the first being Pascal.) I guess because of that I never really saw it as "difficult." Everything is at least somewhat difficult when you're just starting out. Since C was one of the first things I learned that's where all my intuition about languages came from, so everything seemed "natural."

I still program in C++ as my primary language, but that's mainly because of the area that I work in - computer vision. In this field your production code has to run fast. Using something like Python or Java is just not an option (unless you want to wait 3 days to process an 8 hour video.) All the major computer vision libraries - OpenCV, Gil, ITK etc. are in C/C++ so I'm pretty much stuck. Prototyping is done in MATLAB so that speeds up development a bit.

Still, I love it. I don't even know if I can really articulate why, but there is just something fun about having to work with a language that's so close to the hardware. My undergrad degree was in electrical engineering, so to me the low level behavior of the processor is just something that's always in the back of my mind, and with C you can clearly see the assembly level code right through every line - and that's kind of pleasant.

I've always been kind of a math guy - so I have a bit of an obsessive need to understand how every element of the system I'm working with functions, right down to the physics of the transistors. If I don't understand something it's kind of like using a theorem or formula that you have never seen the proof for, or don't really understand. I'll be honest, that kind of scares the shit out of me.

Anyway, so that's a look into the psyche of a person who likes to program in C :)

That being said, nothing beats a nice high level language like Python, and for most tasks that's the best choice. But there will always be room in the world for a highly optimized language like C.

Part of it, for me, is that you know a C++ version is the /final/ version, it's as fast and efficient as it can be. It's canonical, you won't have to do it again.

Better question: why do people continue to waste time starting language advocacy wars, when they could be learning new languages?