One more concept that I've seen people struggle with is the idea that programs/code don't convey meaning to computers - just behaviors. For example, new studen

One more concept that I've seen people struggle with is the idea that programs/code don't convey meaning to computers - just behaviors. For example, new students struggle with the idea that variable names can be changed at will. There's nothing special about a variable named 'personName' - it could be a street address, a function reference, or anything else and the computer just doesn't care. The idea that there is no such thing as intent in the world of computing can be difficult to grasp. This is closely related with the concept that programs are just data. There are ways to teach this though - I personally love the examples of the programming languages where a bitmap is read, or where only whitespace characters are allowed. It can break students' conception that variable names have any meaning to the computer.