It appears that redditor infeKteDx never paid attention to any grocery shopping his family did. Now he is on his own and is totally overwhelmed by the simple task of purchasing bread. The resulting thread is priceless, with suggestions like calling his mom to find out what bread to buy, plus recommendations for different breads to try. Link
No matter how much you teach a child, there is something that will surprise him when he is on his own. For example, you can teach a teenager to drive safely, but if he never paid attention to how roads are laid out, he'll never find his way home. The first day I was in my college laundry room, I met two girls who had no idea how to wash their clothes because they had never done it. Is there something that you never happened to learn from your family that surprised you when you left home?