You know what, honestly? I love that Sisko is consistently affectionate towards Jake, even as Jake grows into a young man. I am hard pressed to think of any other shows that let dads kiss their sons on the cheek, or even just hug their sons, with regularity. No one has to be dying for the Siskos to say they love each other or to physically express that love with out getting all weird about it because of some perceived notion of 'manliness'.
It's a small thing, but something I really love about Deep Space 9.