New guy started at work. I smiled at him in the hallway just to be friendly. My desk is right next to the men's room, and now he sometimes goes out of his way to catch my eye and smile while on his way there (about half the time he walks past). He'll hold the look for longer than normal when he does this. But the other half of the time he doesn't look at me at all, or stares down at his phone instead. If he's this inconsistent, is there likely no interest?