Now that I remember why I gave up Spanish in the first place...
It's not really a linguistic matter like grammar, vocab or accent. No, it is something much more than that: there are too many varieties of the language all over the world.
You have the Spanish people would speak in Europe, and then there is also Spanish people would speak in the Latin area. And as if it is not complicated enough, each region also has its own dialects, which might differ a lot from one another, in terms of both vocabulary and grammar.
Thus, I can't even decide which one to take up in the first place. And as a result, I can't decide which materials to use and then, of course, nothing to learn from. It sucks, if you ask me, the feeling of being confused in a field you are already unfamiliar with.
