Proper Etiquette for a Restaurant That Refuses to Serve You Food?

I've had several lovely meals at Petitte Crevette, all of them before the restaurant expanded into the now defunct Rosebud flowershop space next door. I like Petite Crevette. I like its quirks of running out of half of the menu an hour into dinner. I like its cramped space and idiosyncratic wait and cookstaff. What I do not like is waiting 45 mintues for an appetizer of lettuce, tomato and mozzerella (all cold items, mind you). What I really do not like is waiting another 45 minutes for entrees that never arrived. Watching tables that you came in with eat, pay their check and leave. Watching tables who came in after you get the very food you ordered (here, I think the proximity of tables is really a curse). Asking desperately for bread to sop up the entire bottle of the BYOB wine that you've split with your dinner date, only to be told it was coming, it was being warmed and then never receiving it. Having the waitress make vauge assertions about how the entrees are coming and then never making eye contact again. How can one handle this situation gracefully? In the end, we asked for the check were told "You can just leave," and that we did after dropping an underserved fiver on the table ...