At the very least, I was expecting a scene in which Agent M startles and gets blown away by an armed Agent J, not necessarily because would be mistaken for an alien, but because a sneaking Tommy Lee Jones' face would freak me out to the point of triggering fight-or-flight response too. I kept waiting for that one sequence in which a mothership touches down and releases the leader of Jones' Agent M character's race, Richard Nixon, who then proceeds to exchange with M the trademark symbol for the Nixonians, that two-finger wave thing. No, now that I think about it, I shouldn't have been confused, not just because Tommy Lee Jones is about as black as Will Smith is, but because Tommy Lee Jones must be a special figure in this agency, seeing as how he's a man in black, even though he himself is an alien, or at least looks like one. Oh no, wait, Jones is teaching Smith, I just got confused because I figured that this agency's ranking system was built around how much black was on a man, in which case, Smith would decidedly outrank Jones.
Okay, now, I'm willing to buy this premise about a secret agency that combats and osbscures alien lifeforms, but really, I find it a touch hard to fully buy into a young buck like Will Smith being the one who trains an older dude like Tommy Lee Jones.