I may have a bit of a gift of mimicry for languages - I can usually pull off a passable accent in multiple languages pretty quickly. I've had natives comment that my accent was good. The first few times I considered it politeness, and that probably is a factor, but I've heard it enough over 20+ years that there's probably a kernel of truth in it.

I've done travelled in various areas of Spain, China and Russia (and had studied Japanese years back), and have been able to do rough communication with all of them to some level, but ... when you are doing it, you realize how much you don't know. No, I can't just read any level of book I want, can't understand all the news programs (or the local ramifications), couldn't go see a theatrical play, couldn't conduct business, etc. BUT... the few phrases and words I know, apparently I sound good enough that people have mistaken me (for perhaps 30 seconds, until I keep going) for a native speaker. (well, not in china!)

I remember feeling quite humbled that the 4 year old at a mcdonalds in China was still more 'fluent' than I was as an adult. That gave me a lasting impression, and deep respect for people who move to other countries, develop new lives, and learn a foreign language and culture. I'm not saying I could never do it, but... it's immensely difficult.