#4 The Undertaker once verbally destroyed Bret Hart
The Undertaker is not only respected by fans but also backstage because of just how cool and collected he is. He hardly ever raised his voice, and he was seen as the voice of reason among the boys.
However, there was one infamous incident when even The Undertaker lost his cool, and this was at another legendary superstar: Bret 'The Hitman' Hart. Hart, Kevin Nash and The Undertaker were in a three-way program, and they were trying to tell a story. However, for the story to be told, the Calgary native had to take Kevin Nash's finisher.
Hart would simply refuse to take it. The picture of calm and cool, The Undertaker, lost his temper at that point and confronted Bret Hart, saying not everything was about him.
When the 'In Your House' pay-per-view came around, Hart refused to take the finisher. Listen to Kevin Nash tell the story in the video linked above.