I'll never forget watching the 1984 Olympics as a kid. Twin brothers Phil and Steve Mahre won gold and silver in the slalom at Sarjevo. After Phil finished his race, he used a walkie-talkie to give hints to his brother. I remember thinking, he wants his brother to do well more than he wants to be able to say he beat him. So, while rivalries abound, brotherly love can win out.
Sisterly feuds just as strong
We could of course double this list by looking at rivalries between sisters as well. A big one that's been in the news lately: Pauline Phillips, advice columnist behind "Dear Abby," passed away last month. Her twin sister was the equally famous advice columnist Esther "Eppie" Pauline Friedman Lederer known as "Ann Landers." They were locked in a feud for years.