B major
Although B major is usually thought of as a "far away" key because it has many sharps and is quite far from C major in the circle of fifths, Frédéric Chopin thought that it was the easiest scale of all to play, as its black notes fit the natural positions of the fingers well. Because of this, it was often the first scale he taught to beginning piano students, leaving the scale of C major till last because he thought it was the hardest to play.