Not every interview is easy.

In general, I try to treat interviews as real conversations. It's all an illusion, of course. Most real conversations are not arranged weeks earlier by a team of publicists and don't take place in a brightly lit area surrounded by strangers and cameras that you have to pretend aren't actually there, and they don't take place one after another until people begin to blur together.

At a press event, though, that's exactly what happens, and so it becomes hard to make it feel natural. When you are dealing with cast members like Justin Bartha and Heather Graham for a film like "The Hangover Part III," it's exponentially harder. That's not a reflection on either of them, though. It's more a matter of the roles they play in this particular film.

As in both of the previous "Hangover" films, Bartha gets sidelined early and spends much of the film off-screen. Graham returns playing her character from the first film, but it's really just one extended scene where she appears. Altogether, the two of them probably have about 20 minutes of total screen time, and much of it serves the function of the story. It's harder to find something to discuss with them, so it helps that both Bartha and Graham are charming and work hard to make sure that the interviews are engaging and fun anyway.

I ran part of this earlier with Bartha talking about the possibility of a third "National Treasure" film, and in that franchise, I'd argue Bartha plays a more pivotal function. He certainly has more to do. And frankly, I'll sit down with Heather Graham under any pretense. I think she's still just radiant, and that's not really a physical description. It's more about the energy she gives off on film, the force of her personality. It's true in person, too, and I think it's just her. It's not even something she seems to consciously switch on. She just has a very strong presence, part wide-eyed optimism and part carnal charisma.

I have to say that one of the things I liked most about "The Hangover Part III" is that they didn't feel the need to pile any misery onto Graham's character. There are certainly much darker fates that Craig Mazin and Todd Phillips could have imagined for her, and instead, the place we find her is almost uncharacteristically nice. It makes some of the other bad behavior we witness more palatable.

"The Hangover Part III" opens Friday everywhere.