When someone likes you at work, they may do things like: going to the kitchen when you're there; involuntarily staring at you (a lot) when you're not watching; befriending your coworkers - so that he can get closer to you; asking your coworkers about you; asking you out (outside working hours); taking a break when you do (and consistently doing it); going to the bathroom when you do (and doing it often); sending you emails or instant messages more than they do with other coworkers.