"I knew you were trouble when you walked in / So shame on me now," Taylor Swift laments on 'I Knew You Were Trouble,' another promotional single from 'Red,' due Oct. 22. Other than 'Back to December' off of 'Speak Now,' this may be the first single in which Swift, however indirectly, takes responsibility for her role in a failed relationship -- and that maturity suits her, though it may not always make for easy listening.

The song has clear dubstep influences in its production and instrumentation, and it's a purely pop confection -- but, in her masterful crossover way, Swift manages to sneak some country twang into her vocals every now and again. Swift also sticks to her rainbows and unicorns storytelling style, opening the song with "Once upon a time," hinting that while she still loves fairy tales, she may finally be beginning to understand that they don't always have happy endings.

"Oh! Oh!" she wails post-chorus, followed by an audibly frustrated, stunted, "Trouble, trouble, trouble" refrain. The girl sounds as upset as her lyrics suggest, and the deliberate distortion creates a sort of ironic cohesion to the track -- because it's supposed to be "chaotic."

That cohesion may not be for everyone, however, as there's a lot going on in the song. There are plenty of different sounds, harmonies and genres at work, and while they thematically fit together, they don't always blend seamlessly, making for an occasionally jarring and awkward listen. Swift's pop base will likely eat this up, but her country fans may find this multi-layered, bitter breakup track a tough (or jagged little) pill to swallow.