When I was writing my chapter on the verse paragraph last fall, that's all I was interested in. I was obsessed with prosody. When I was looking at materials for my chapter on the aphorism, I became an aphorism nut. I bought books on it, wrote many boring blog posts about this genre. It seemed, all of a sudden, that I had been obsessed with this my whole life. I remembered papers I had written as an undergraduate that my memory had let slip away. I have also had obsessive interests in translation theory, in jazz drumming, and many other things.
Cada loco con su tema is a Spanish proverb that means, more or less, that every crazy guy has his obsession, or that that obsessed people seem crazy. I have more than one "tema."