In 'Richard III', how is it that we can be so interested in Richard, and even sympathetic towards him, when he is so completely evil?

‘Richard III’ opens with a soliloquy by Richard, introducing himself to the audience and revealing many things about his character. One thing we learn about him, is his sarcastic humour,

‘Now is the winter of our discontent

Made glorious by his son of York,’ which could be the ‘sun’ in the sky, or Kin

‘Why, I in this weak piping time of peace,

Have no delight to pass away the time,

’

 i

n which he uses