See, "Chainsaw" isn't necessarily an awful song, it's just dull and boring. And a large part of that has to do with the melody, which does absolutely nothing for me, especially during the verses.
But the biggest issue I have with "Chainsaw" is Kimberly Perry's performance. For a vocalist who has delivered some stellar performances in sassy numbers like "DONE." and "You Lie", her delivery on "Chainsaw" is surprisingly immature and forced. It's a darn shame because if the delivery had been even half as good as it was on the aforementioned two singles, "Chainsaw" could have been miles better than it actually is.
Pioneer is chalk full excellent tunes that showcase TBP at their best. Unfortunately, "Chainsaw" is not one of them.