Writers strive to reveal their fictional characters in a lot of ways including dialogue. I think how Lance Armstrong expressed himself in his interview with Oprah makes a fascinating lesson in subtext—what people are saying, or what attitude they have, that is different from the surface meaning. For instance, Armstrong said:
“And I mean that, as I try to take myself out of the situation and I look at it. You overcome the disease, you win the Tour de France seven times. You have a happy marriage, you have children. I mean, it's just this mythic perfect story, and it wasn't true.”
If you take yourself out of the situation you create a distance—which can be useful for analysis but it can also be a way of disconnecting from it.
Talking about yourself in the third person (which is called llleisim) can also reflect an inflated view of oneself, as though even you are so in awe of yourself that you have to speak of yourself as someone you regard with wonder. Salvador Dali did this at times, including the statement, “Dali is immortal and will not die.” Wrestler "The Rock" was fond of the practice as well.
A similar effect comes from passive phrases like “mistakes were made” (instead of “I made mistakes”). Politicians going back to Ulysses S. Grant have been fond of this phrase. Ronald Reagan said it in his State of the Union Address (regarding the Iran-Contra Affair), and so did Richard Nixon (Watergate), Henry Kissinger (supporting assassinations in South America), and Bill Clinton (fund-raising scandals). William Schneider called it the “past exonerative” tense.
Your readers won’t analyze effects like this in the dialogue you write, but they’ll get the message nonetheless.(There's a lot more about creating vivid characters in my book, "Your Writing Coach" and also about how the great classic and modern writers do it, in my other writing book, "Your Creative Writing Masterclass," both published by Nicholas Brealey and available from Amazon or your other favorite book seller.)