Do you remember Binbougami ga!? You probably did not watch it while the few who did usually proclaimed how utterly dull it was. I was originally one of the persons who did not watch it, the reason being how, well, utterly dull it seemed to be.
But for some reason I became more and more interested in it, surely the catchy opening and ending song helped with that, and shortly after it had finished airing I sat down and watched it. And boy did I fall in love with it quickly. I ended up breezing through all thirteen episodes in only three days, which is a rare feat for me.