I really, really enjoyed Good Oil, but I had to think on it for a few days before pinpointing why I enjoyed it so much, because there were a lot of elements that should have irked me, but instead, they worked. There are quite a few comprehensive reviews already on Goodreads, so I'll just say that this story worked for me where other similar ones don't for a few reasons: 
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 1) The situation, with the group of young people, 15-24, working together is so, so authentic. I think it's something most of us have experienced and the relationships that evolve out of those situations are so important--at the time. The scenes in Woolies were my favorites, even though they were minimal. 
 2) Amelia's infatuation is mortifyingly real. I actually buried my head in my pillow at one point when reading, because I wanted to die of embarrassment for her. 
 3) Chris is an interesting and kind of typical 21-22 year old English major college student. He listens to Jeff Buckley obsessively. He writes angsty stuff in his journal. He drinks too much. He wants to be a grown up, but doesn't know how. 
 4) The issues explored with regard to Amelia's parents' relationship are painful and so flipping well-done. 
 5) There's no tidy resolution, which would be unrealistic either way. 
 6) It's just such a well-done Inappropriate Relationship story--the only other one I've read that worked for me is Kelly CK Martin's The Lighter Side of Life and Death. 
 7) The writing it witty. 
 When I finished Good Oil, I desperately hoped that Amelia would eventually let go of her Chris obsession and go out with an Age Appropriate boy. Maybe Chris will come back eventually and they can be friends, but I wasn't necessarily rooting for them to get together when Amelia's older. It also spurred me on this whole tangential train of thought about the challenges, especially for "youngsters" (As Chris would say) of boys & girls/men & women trying to figure out their relationships--and not just the big R relationships, but how at that age, the only male-female relationships that are "normal" are big R relationships. Anyway, that's superfluous to the plot and this review, but I figure if it left me awake, thinking about how weird all that was when I was 15-21, that's the mark of a good book. 
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 Recommended, but Good Oil definitely isn't for everyone. I'd actually love to read a sequel to this one, and I'm not usually a big fan of sequels. (I'm thinking how The Piper's Son was such a perfect sequel to Saving Francesca, even though--and maybe because--it was unnecessary.)