Correcting people?

I've been told it's always been a problem of mine, correcting people when they slip up or are mistaken. I guess being corrected on something can be a little demeaning, especially when it's by someone your junior or someone you're supposed to have authority over. But how bad is it really? I don't recall ever being offended when someone corrected me, and in fact I thank people on the internet when they catch a grammatical or spelling error in stuff I write because I'm happy they share my appreciation for good English. I can't wrap my head around this fram of mind that refuses correction; don't you want to learn from your fellow man?

The thing that stirred this pondering was my stepdad talking about the World Cup today. He kept saying that "Guyana" was through to the next round of play. I misunderstood at first and thought he meant the South American country and told him they weren't through. Then I realized that he meant the African nation of Ghana, and further corrected him. He got angry and said, "What's the fucking point? You know what I meant." I can tell you the point; I don't want someone I know to appear like a fool in conversations when I can correct a simple error, so don't get offended when I'm trying to help you with no hint of condescension. You're welcome.