I tried to explain again. 'Perhaps it would have been easier if I said that not being able to find something is like suddenly not remembering the words to your favourite song that you knew off by heart. It's like suddenly forgetting the name of someone you know really well and see every day, or the name of a group who sang a famous song. It's something so frustrating that it plays on your mind over and over again because you know there's an answer but no one can tell you it. It niggles and niggles at me and I can't rest until I know the answer.' 'I Understand,' he said softly.