That time Batman cared a.k.a. when he revealed his ID.

There was some talk during Morrisons' run about him not playing up the fact the Joker saw Batman unmasked. The thing is--he already knew. I think it was apparent in Death in the Family that he figured it out. Well actually Batman flat out told him but stupidly saying he knew Joker killed Jason. Yes Jason not Robin. At the U.N. Joker starts laughing when he sees Bruce Wayne.

Think maybe a first name isn't enough to make the connection. Well Batman was kind enough to give his arch-enemy his victims' last name as well. The Joker doesn't particularly care about Bruce Wayne just Batman. He might be insane but he's smart. He can put the pieces together. 

The name is one he remember very well. In fact he used it to gloat Nightwing on during a fight. (Which briefly resulted in him killing the clown.) I kind of miss the Bat family getting this defensive over Jason.  Even if Batman was incredibly reckless.