Just a note to salute the humble 'seam ripper' or 'quick unpick' as I have always called them (that's what they were called in grade 8 home economics). Quite often I reach for this sewing tool when I am at my crankiest because I have just stitched something wrongly so its probably nowhere near as celebrated as it should be. The best one that I have ever used is by Clover (pictured) and is available at all good craft and sewing shops - the cheapie ones just don't cut it I'm afraid!