Was helping a friend with his programming assignment yesterday and realized most of the difficulty in doing something that I have already learned is finding out what the teacher wants. I wasn't in his class so I don't know what his teacher had told him but we somewhat struggled understanding what was needed to complete the program properly. Doing the same problem back when I took the same class a year ago, I can only recall doing the assignment with ease.

So it makes me think what else gives us trouble when trying to remember we have done before? Does riding a bike give us a little trouble after some time? Using a computer? Driving? How hard would the task actually have to be to give trouble when remembering it from the past?

I couldn't think of a task where it could give trouble as the above all seem hard to forget.