Most single siblings are mean because they are unhappy. They see all these newly forming families and it makes them feel left out so they are mean as a result.
Single Siblings - 2013 was released on: USA: 15 March 2013 (internet)
If you mean Hitler, he had no siblings
siblings
Single Siblings - 2013 The Workout 2-4 was released on: USA: 25 November 2013
Single Siblings - 2013 The Farnsworths 2-2 was released on: USA: 11 November 2013
Single Siblings - 2013 The Couple 1-9 was released on: USA: 10 May 2013
Single Siblings - 2013 The Dog Park - 1.3 was released on: USA: 29 March 2013
They may be jealous of them.
Do you mean knockdowns?
Single Siblings - 2013 Lost Lunch 1-5 was released on: USA: 12 April 2013
Single Siblings - 2013 The Book Shop 1-2 was released on: USA: 23 March 2013
Single Siblings - 2013 The Set Up 2-3 was released on: USA: 18 November 2013