Cable Cord Cylinders
Called a ferrite core, the cylindrical lump at the end of your cord come with magnetic iron oxide. It is useful because it prevents high-frequency electromagnetic interference. If you happen to be close to a speaker, your call will be interrupted by weird noises. The core prevents these interruptions.
Apple Power Cord Wings
If you own a MacBook, you will see wings on the cord. If you pull them up, you can simply wrap the cord around this feature. This is great if you want to avoid making messes with the cords. Voila!