I never thought this day would come, but now that I have successfully completed (+ passed!) a Spanish 321 (returned missionary-level) course at BYU, I think I can finally say that I would be able to survive on my own for at least a bit if I was somehow dropped off in a Spanish-speaking country or something. (:
I know I probably will never be able to consider myself fully "fluent", but taking that class last semester was a huge step for me: I skipped the transition course and took it entirely as an elective course (I had already fulfilled the foreign language requirement for my GE's) - so it was definitely a challenge. But I loved every moment. Just love Spanish!