Monk who cut off his eyelids “^ _^”

Bodhidharma (approx 5th/6th century CE) was a legendary Buddhist monk well known in both Chinese and Japanese buddhist lore. Some of his mythic feats including meditating in a cave, facing a wall for nine years.

Yes, nine years. He was so angered that he fell asleep during the seventh year that he cut off his eyelids to prevent it from happening again. He also once ordered one of his disciples to cut off his left arm to prove his dedication. Yikes.

 According to legend, Bodhidharma is also responsible for creating Chinese martial arts. Having arrived at the Shaolin Temple, he was disturbed by the monks poor physical fitness which were preventing them from meditating for long periods. He taught them a system of exercises to strengthen their body which eventually evolved into Shaolin kung-fu. Can someone explain to me that why, if Bodhidharma was such a high practitioner of Buddhism, is he always depicted as grumpy and with an angry face?