Friends who Spy

If I found out that one of my friends was spying on me I would be pretty pissed to say the least. At first I would be very skeptical as to why they were spying on me, and probably would not talk to them for a while. However once I moved on from the initial pissed off stage, I would confront my friend as to why he/she felt it necessary to spy on me. If it were for a legitimate reason, like checking on me to make sure I wasn't in danger, or such things like that; it would be a lot easier for me to forgive her for being a concerned friend and would actually be sort of flattered that someone cares enough to spy on me (creepy as that may sound). However if she was spying on me for a petty selfish reason, like trying to find things to blackmail me with, then I would not be able to forgive her, and would probably question if she were a true friend or not. Either way it would easily become a very sticky situation no matter how it's handled, either I would have a very close dear friend who is generally concerned about me and was only trying to help, or this so called friend has other motives then just to be my friend.