What does "Fatal error: Unexpectedly found nil while unwrapping an Optional value" mean in Swift?

Hi everyone! I just started learning Swift and encountered an error I can't understand. I have a simple User class, and I'm trying to print the user's name to the console. Here's my code:\n\n```swift\nclass User {\n var name: String?\n var age: Int?\n \n func printName() {\n print(name!) // Crashes here!\n }\n}\n\nlet user = User()\nuser.printName()\n```\n\nWhen I run this code, the app crashes with the message: "Fatal error: Unexpectedly found nil while unwrapping an Optional value". I understand it has something to do with name being an optional string (String?), but I just want to print it. Why is this happening? I'm not doing anything complicated.\n\nI've read that you can use "!" for forced unwrapping, but it doesn't work if the val