I can’t remember exactly how they described it, but someone on the DS9 documentary said that Avery Brooks spoke like he was performing a jazz concert that only he could hear. He really is hard to predict haha. One of my favorite small moments for Sisko was when Odo came into his office to give a report and Odo starts quietly singing. Sisko gives the slightest glimmer of a smile and starts snapping along with the beat.