I hate... when that little plastic tip comes off the end of a shoelace and the shoelace (that never came back through the holes) all of a sudden needs to be constantly shoved through the eyelet with a pencil or some other pointy, slender object, then the end finally frays so bad that when you pull on the shoestring only part of it comes through the hole and leaves that wad of material on the inside of the eyelet.