If you’ve read my previous installment in the “P is for Pop Songs” series, you already know that most of the bands I plan to write about start with the letter P. But this one’s different. Because this one’s METAL. Let’s talk about Metallica. My very first boyfriend was a guy from New York. The Bronx, in fact, which he claimed was a much maligned borough, mostly because despite news reports to the contrary, it was much less frequently on fire than, say, Staten Island. (Which is, in fact, true, but possibly only because Staten Island’s dump often spontaneously burst into flames. Then again, this is true for most garbage…