One thing I noticed in the latest Justice League trailer is that a lot of the heroes are smiling. This is likely a conscious decision by Warner Bros. after many critics said that Batman v Superman was too dark and lacked “fun”. In the latest issue of Empire Magazine, Ben Affleck says that fans will see Batman smile as well.
“You get to see Batman smile,” Affleck told Empire. “For the first time!”
I just rewatched Batman v Superman last night, and I think Batman did smile in that movie… or at least gave a smirk (pictured above). After he shoots Superman with his kryptonite grenade, he has a delighted look on his face like he’s very proud of what he just did. He also smirked when he said “well, here I am” before the big fight. Perhaps what we see in Justice League will be a full-on smile, clenched teeth and all.
SOURCE: Empire Magazine November 2017