White Girl Problems by Babe Walker (2012)
Recommended by a co-worker, this looked fun. And it was! I love when an author creates a character who is so self-unaware that you can't help but like them even though they're incredibly irritating.
Babe Walker ended up in rehab after spending $246,893.50 at Barney's, and is writing her memoir to explain how she got there. With chapters like "I hate my horse", "Sorry for texting you ninety-three times last night" and "I miss you, unless you miss me, in which case I'm over you and into me being me", this novel is incredibly hilarious and over-the-top and somehow even a little endearing.
Followed by the equally hilarious Psychos: A White Girl Problems Book.