There are a lot of good books on etiquette that cover both cultural norms, courtesy and manners that would have made your life a lot easier. In fact, I like to read books on foreign etiquette before traveling to another country simply because I don't want to offend anyone.

Unfortunately, no one was going to correct you on your mistakes. Since you're not a child, people assume you know better and don't want to presume you don't just because you didn't grow up here.