That big reason, at least from what we’re seeing, is that Harley Quinn is either talking about, or actually was, pregnant.
Seeing as The Joker was supposedly cut from most of his appearances in Suicide Squad, there’s a lot of potential evidence that could be on Warner Bros’ cutting room floor.
However, there’s a big moment that’s still in the film that has us thinking about his relationship with Harley, and why he’s so intent on chasing her.
The icing on the cake is the fact that actual baby clothes are set out around the knife formation.