Blurred Lines by Robin Thicke. It came out just after Breezeblocks by Alt-J and a friend and I argued over which artist/song would blow up the biggest.

I went with Blurred Lines which ultimately stayed atop that charts for 12 weeks in 2013. (Breezeblocks never topped the pop charts but was top ten on several Indie charts).

We're still friends. We were just having fun talking about music. I don't even particularly go for pop in general but that opening hook gets me every time.