In “Love in L.A.” by Dagoberto Gilb, why is Jake "both proud and sad about his performance"? What does this mean? What does author Gilb mean when he says he identifies with Jake? What kind of character is Jake?

When Jake returns to his car, he feels "both proud and sad about his performance," as he has pretended to be someone else with Mariana. He is clearly broke, but he pretends to be an actor and a musician. He also tries to woo her, and she gives him her number in the end. Therefore, he has conducted a kind of performance with her, and he feels proud about it because he believes that he has fooled her into believing he is greater than he truly is. He also feels sad because he has lied consistently and pretended to be someone he isn't in an attempt to deceive her. He might also feel sad because he can't measure up to the person he pretends to be. 
The author, Gilb, writes that he identified with Jake because he was also confused about who he was. The author writes, "Was I a construction worker pretending to be a writer? Writing was this full-of-it dude who was getting me." Gilb was trying to make a living as a construction worker, but the beauty and sexiness of writing intrigued him (much in the same way that Mariana intrigued Jake). Gilb felt he was kidding himself about being a writer, much in the same way that Jake was kidding himself about being a glamorous actor and musician. 
Jake is a fairly consistent character. At the beginning of the story, he dreams about the new car he will get and how glamorous it will be, with its "crushed velvet interior." Even after he gets in the accident, he is still, at the end of the story, dreaming about the interior of the new car he wants. The fact that he has consistently lied to Mariana does not trouble him. Though Jake is a static character in many ways (because he doesn't change), he is a round rather than flat character. The reader wants to know more about Jake's motivations. For example, why does Jake lie consistently? Does he dream about being a star, and what has held him back from reaching his dreams? As a character, Jake troubles and confuses the reader, causing the reader to want to know more about him.