"I'm frankly not too big on opera," Jane Fonda confided at the opening of the Metropolitan Opera's season last night. "I don't like the inevitable tragic-ness of it." Indeed, Lucia di Lammermoor was a major downer, although an entertaining one: Natalie Dessay, in the title role, brought down the house with a hair-raising mad scene. Has Jane ever lost it like that? "In a scene in a movie, but never in life," she said. "My mother did that for me. I didn't have to go there again." Uh, okay, dead mother, we're super-uncomfortable now. Oh, hey, it's Barbara Walters!