Beyonce; Is She Really 34 or Older?

The Beyoncé age conspiracy theories have returned thanks to an interview the singer's dad Matthew Knowles gave to a New York radio station. Beyoncé says she's 34 and singer Pink is 36.

Knowles said that Pink and Bey were the same age back when Destiny's Child was starting out. . . so wouldn't that mean that Beyoncé is 36? After the singer appeared in "Cadillac Records" with Gabrielle Union in 2008, Union mentioned that she and Beyoncé "have been friends since we were teenagers," even though Union is nine years older than Bey.

Why do people lie about their age?