The above is an interesting finding of which are your favourite keys according to your horoscope. (Just for fun but you can still find them out.)
A key signature is a musical notation which is a set of sharp or flats symbols placed together on the staff. It’s a common misconception for students : The more the sharps or flats in the key signature, the more difficult to play the piece. What students care about is the numbers of sharps or flats but not the key itself. The importance of a key is to let people know the intended tone colours and emotions of the compostition. You may have your own interpretation of emotions to different keys but in general the keys relate to most people, e.g. major keys relate to happiness and pleasure while minor keys are more like depression and lament.
The following artcle is about affective key characteristic and it’s from Christian Schubart’s Ideen zu einer Aesthetik der Tonkunst (1806).
Translated by Rita Steblin in A History of Key Characteristics in the 18th and Early 19th Centuries. UMI Research Press (1983).
Another version of emotions of the keys is in Chinese. But in fact the colours of keys stated here are not that scientific and I should have another post about the colours of keys later. Different composers seemed to have various associations of colours to the keys.