THE MISHEARD:

But When You Leave Me
I'll Be Wishing I, Wishing I, Wishing I Was Dead

The story:

I heard the song on the radio, and thought, "Well, these lyrics make sense to me". Then I saw the video on MTV a couple of days later, and sure enough, on the bottom left corner of the screen at the end of the video was the correct lyric, and hence the real title of the song. I still think mine's the best, though.