Richard was rash

Richard was more like his brothers than he would have cared to say. He
was fond of bastardising his enemies, but he had more in common with
them than he would've admitted. Self-centred & ruthless, but more like
Clarence in his rash ventures: Richard's mishandling of the encounter
with Rivers, April, 1483, the unbelievable claim to the crown, his
foolish charge at Bosworth!

Richard had celerity of mind, which was impetuous: like his Father's
charge at Wakefield while hopelessly outnumbered, Clarence's coat
changing and pinpricking troublemaking!

Richard claimed a similarity to his Father and so he was in his
ambitious and impetuous nature.