Hathaway, who is also one of the film's producers, answered as sweetly as anyone could.
"I like beautiful movies, and I think they come in all shapes and sizes," she said.
Sometimes, actors will defend their indie choice by finding a similarity between the independent work and his or her well-known role in a blockbuster.
That's what happened when Mark Ruffalo talked about his role as a manic-depressive father in Maya Forbes' semi-autobiographical drama "Infinitely Polar Bear."
Ruffalo, one of the stars of Marvel's "The Avengers," described his bipolar character as "the low-budget indie version of the Hulk."
The main reason actors flock to the sorts of indie films that play Sundance is because that's where the interesting roles can be found.
Blockbuster movies are, after all, exercises in minimizing risk and there's nothing riskier to a producer or casting director than picking an actor who doesn't already fit the audience's preconceived notions. That's why Ray Liotta always plays a mobster or a dirty cop, or why Drew Barrymore always plays winsome romantic interests.
But indie films let actors break out of those cocoons and take chances, because they're not betting with the house money. In many cases (like Hathaway in "Song One" or Aaron Paul in "Hellion"), the actors are also producers, so they have skin in the game.
Every year at Sundance, particularly in the U.S. Dramatic competition, there are notable performances from actors who wanted to show Hollywood there's more to them than just the expected. Here are three great ones from this year's festival:
Bill Hader, "The Skeleton Twins" • We already knew, from "Bridesmaids," that Kristen Wiig could handle pathos alongside comedy. In director Craig Johnson's dramedy, Hader plays a struggling actor who attempts suicide, which leads to an uncomfortable reunion with his twin sister (played by Wiig). The old "Saturday Night Live" chemistry is intact in the comic segments, but Hader surprises with a tender performance in the serious passages.
J.K. Simmons, "Whiplash" • Simmons' early prominent roles, such as a white supremacist inmate in "Oz," were loaded with menace, but lately he's become cuddly and comical (as in his upcoming sitcom "Growing Up Fisher" or his Farmers Insurance commercials). In "Whiplash," he plays a hard-ass jazz band conductor who drives an ambitious drummer (Miles Teller) to the breaking point. Simmons' fulminating tirades and quiet manipulations are spine-chilling.
Melanie Lynskey, "Happy Christmas" • The New Zealand-born actress gets to use her own accent for a change in Joe Swanberg's largely improvised comedy, playing a novelist feeling creatively stifled as a stay-at-home mom. Lynskey has done comedy (a recurring role on "Two and a Half Men") and drama (notably in "The Perks of Being a Wallflower"), and "Happy Christmas" lets her show many facets as a woman both delighted and frustrated by motherhood.
Sean P. Means writes The Cricket in daily blog form at www.sltrib.com/blogs/moviecricket. Follow him on Twitter @moviecricket, or on Facebook at www.facebook.com/seanpmeans. Email him at firstname.lastname@example.org.