Backtrack a few years. Give us the setup--sixteenth birthday, parents forgot about it--then a montage of high school scenes under the opening titles. Pretty basic.
Samantha (Molly Ringwald) talking to herself is a bit too "voiceover" without being a voiceover. I'm not sure I approve.
And then there were few words. But, I just gotta say, the chemistry between Ringwald and Michael Anthony Hall in the half car is awesome.
And, Samantha is my kind of character... that is, a character like me. Obsesses about a crush that shouldn't amount to anything, practices what she's going to say to him ahead of time, then fails to say anything. Been there. The Geek (Hall), on the other hand, has a bizarre level of confidence for being a geek. Much more than Hall's character in The Breakfast Club. Much more than I ever had at that age. Hell, more than I've usually got to this day.
But, getting back to performances, the scene with the Geek and Jake (Michael Schoeffling) is good writing, and Hall does well with it, but I really with Jake had more personality to him. I mean, all we know about him is that a) he is not content with his girlfriend (but we don't know why), b) he is willing to hand her over to the Geek to take home and (maybe) use for passed-out-drunk sex. Blane (in Pretty in Pink) and Amanda (in Some Kind of Wonderful) at least feel like they've got lives beyond what we see on screen. Jake is more of a plot device.
Ultimately, the film involves some racist caricaturing, implied date rape (or at least the approval thereof, even if the act never happened), and it's still pretty funny. That's the 1980s.
Also, like many a John Hughes film, even the caricatures feel like actual characters, the dialogue feels natural. And, he captures something real about being a teenager, especially a teenager in the 80s.