Vosotros?

Oh hey,
Remember in high school and even in college when we would learn new verbs in Spanish and every time, the teachers would tell us, "Oh, don't pay attention to vosotros, you don't/won't need to know that," and would continue on with the lesson as if no pasa nada?

MENTIROSOS!!!!!!

If there's one thing confusing me more than anything here, it's their constant use of the vosotros tense instead of "tú."  I have never fully understood when/why/how you use the vosotros (gracias a todos mis profesores) and so I never use it.  While I don't think it matters that I don't use it, it matters to me that I can't automatically recognize when someone is talking directly to me.  Very frustrating.


Other new/different things in the language here (things that are not to be blamed on my teachers):

• "ll" is not pronounced like a "y" sound, but rather a "zsh" sound.  
• En Buenos Aires, here = "acá," not "aquí"

Edit:

sooo..... Apparently I was wrong, and my teachers shall receive no blame.  Because, here, we're not using "vosotros," we're just using "vos," which is infinitely easier.  It's basically just a really lazy form of "tu" and I LOVE IT.