He knew rock and roll was where it was at. The Stones "Tell Me" makes the Volpe's introduction scene work to this day. I hear millennials praising it.
The soundtrack is a big part of what makes "Mean Streets" great. My favorite: Charlie looking adoringly at himself in the mirror while putting on the monogrammed shirt his mother bought him, while the Chantels are singing, "I Love You So." Also, Charlie, Tony and Jimmy driving to Joey Catucci's pool room while the Paragons are singing "Florence" --quintessential New York Doo Wop.
