David Letterman's decades-long feud with Jay Leno began in 1992, when the latter maneuvered his way into Johnny Carson's seat at NBC's "Tonight Show," a rivalry so famous it was the subject of the 1996 film, "The Late Shift."
Letterman had a few kind words for his friend-cum-adversary in an upcoming interview special with Oprah Winfrey, but he coupled them with a dig at Leno's supposed "insecurity."