Well, I can understand English almost like my first (Croatian) while Italian is a common language in this region an everyone uses it (and so do I) comfortably. But my spoken English (and written of course) must be extra filled with mistakes.
Can understand some German too.
But than I never met an English or Italian speaking native that has learned another language properly. Well the Italian has a problem being.. I don't know how to say this in English.. "marked".. That is - the Italian speaking people even when learning other languages will probably have much heavier influence of their first language on the second in pronunciation than some other nations. Don't know the details, the girlfriend (she is a linguist, teaching at the university) explained me this once, but I can't remember more than this.
As for English speaking nations I'm not sure if that same thing is the case or is it the simple fact that having the world's lingua franca for the first language there is no need to learn anything else. Living in a small country (there are cities with two times and more inhabitants than my country) you are sometimes forced to learn other languages, and the last 5-10 years English imposed itself (before that German and Russian were learned a lot more, Italian, French and some others to a lesser degree as well as classical languages like Latin or old Greek). So if one starts learning English in the third elementary, and has it in the high school and possibly (depends) in the university that person will sometimes learn it for 14 years and maybe know it better in some areas than some native speakers. But that's not my case
And I must say that it's easier to understand someone who has learned English than some native speakers as it can differ a lot from country to country. Not to mention places like India (not native but official and sort of lingua franca in a multi-lingual country) where it is heavily mixed with other things. And the US kids slang as someone mentioned is almost as difficult
Well at any rate people are usually happy to see others speaking their language even if just a few words (like learning a few common word and phrases when traveling somewhere). I live in a region that in summer has much more tourists than inhabitants and I never heard bad comments when someone learns a few words even if poorly, how could anyone be annoyed by that?