Carmelita's, like many other amazing independent restaurants in the area, is hidden in a strip center, near a Blockbuster. The decor isn't exactly classy, but it's a comfortable atmosphere and you will see families, couples, and singles eating around the clock.
The portions are huge, the price is right, and a miniature Mexican flag comes stuck into every entree. For an appetizer, try the botanas, a sort of baked nacho smothered in beans, sour cream, cheese, and beef. Entrees are uniformly great--the Del Rey wet burrito is a perennial favorite. Carmelita's has amazing flan and fried ice cream, and the cups for soda, water, and tea are HUGE.
The waitstaff is all very friendly and billingual, but you won't feel uncomfortable, even if you don't speak a word of Spanish. Carmelita's wins Best of the Bay every year--leave the chain restaurants behind and find out why.