Originally Posted by 5kgLifter
Just turn around, say "sorry, didn't see you there, what can I do for you?" simple...
if anything will have the effect you want and also be appropriate for the work place, it's 5kgLifter's suggestion.
from having been in similar situations, though, my experience is that this will not be an issue that gets resolved. it's because:
1. the person is so ignorant that she/he won't take a hint, no matter how clear the hint is. this is because they're a bit egocentric and don't see themselves as having an effect on other people.
2. in light of 1., your only options are a) tell her directly that she's making you uncomfortable, b) continue dropping useless hints, or c) endure the irritating behavior. of course with a), you risk a major conflict that could possibly make your work place even more uncomfortable than it already is.