There's a long list of actors who crash and burn, or just plain disappear, after a single star-making, early-career performance. Cuba Gooding Jr. may be the prototype, but see also Jaye Davidson, Linda Blair, Linda Hamilton, etc. But every bit as frustrating as an obviously talented performer who never again does anything of note after making an initial splash is the actor who gives a single indelible performance and then goes on to a successful, entirely respectable career without ever recapturing that magic. I know no better example of that phenomenon than Naomi Watts, a bona fide superstar who has been competent and thoroughly unremarkable in a long string of big-time Hollywood roles, but has never lived down – or even approached – the performance that made her a somebody in the first place.
It's arguably inevitable that I would feel this way, since I consider Mulholland Dr. to be one of the greatest films ever made, and anyone in any way associated with it walks on water as far as I'm concerned. But Watts's performance as Betty Elms / Diane Selwyn is so fearless, so committed, so entirely submerged in the movie's terrifying freakshow universe, that it's in a class by itself – as essential to the film as Lynch's singular aesthetic. The obvious reference point is the incredible audition scene, which is at once hilarious and deeply disquieting (as well as thematically pivotal), but what sticks out in my mind is Betty's arrival at LAX, her face a perfect vision of the wide-eyed excitement and sense of possibility that brings countless young people to the shark tanks of LA and New York on a daily basis.