Found this comment on Eonline website and I really agree.
David should really retire, Kristen owned him and was the funny one in the interview.

I love the fact that Dave Letterman went out of his way to put Kristen down every single time and she was able to rise above him each time. But what I truly loved the most is the fact that Kristen didn't hold back on her rebuttal about the brutal killing of wolves in Yellowstone. I have never seen Dave work so hard, SO HARD, to win an argument with anyone, especially with a 20-year old beautiful girl whom he probably didn't expect would hold her own towards him. I think Kristen took Dave to task this time because in the interview, it was Dave who was putting all the effort, TRYING SO HARD in fact, to "win" and "look cool" over her while Kristen effortlessly just let him be Dave without being afraid of his continued onslaught. Definite WIN for Kristen on this one. And as she has proven time and time again, she doesn't need to kiss anyone's azz. LOL Because especially in this one, Kristen totally owned Dave's azz! LOL! You rock Kristen!