From François Truffaut's Stolen Kisses (Baisers Volés, 1968). Hapless Antoine Doinel (Jean-Pierre Léaud) says the names of his two tangled loves over and over, and then--the best--his own.
This scene is so good, it's like existential slapstick. I used to mutter to myself sometimes, "An-TOINE doinel..."
It perfectly catches the befuddlement of existence, especially when we're young. We ask, "Who am I?" the philosophical question of the ages, but further, "Who are these other people? ...and what am I DOING here?!?"
These questions together are both poignant and hilarious, and Léaud gets them just right.
I would contrast this with the scene in Moonstruck (1987) when the mother of the family, Rose (fifty-six-year-old Olympia Dukakis), turns down a proposition from a philandering professor (John Mahoney).

When he walks her home and asks to come in, she turns him down, and he guesses it's because there's someone home.
No, she says, it's because "I know who I am."
When I first saw that movie, I was in my mid-twenties, not much older than Antoine, and I didn't get her reasoning at all--her line felt like a nonsequitur. Now I get it. Rose has stood in front of her mirror often enough to know who she is, who this guy is, and what it would look like if they stole kisses together. Like a martial artist, she simply steps out of the way of this train-wreck of a man.
I don't know if Antoine ever figures this out. I think he might forever remain like Mahoney's professor, "a boy who likes to be bad." Unfortunately, we have met the type before. Not so charming at forty, fifty, sixty... But so beautiful, so recognizably us, caught on film at twenty.