Unsure about Friendship at Work?

I work for a small company, and I share the front lobby with the office manager, who is a very nice woman, and we get along well. She seems to always be doing things for others and for me. It seems that she wants to be friends with me and she will do something very nice for me, but then the next day she shuts me out or acts unfriendly.. almost as if she is trying to keep her distance from me, or keep me at bay. I feel like its her way of saying, "I like you, but you can only know this much about me, and I will only be nice to you when I feel like it."
I understand it isn't a good idea to be too personal at work, but she is always doing friendly, nice things for me. I need help understanding how I should feel about this. Its unfair for her to throw me off track all the time with her irratic friendliness. I want to tell her "Either be my friend or don't." but that would affect our working relationship. Any advice?

Just remember, you go to work to work, (for money), if you make friends- great, if not, still great, you aren't loosing out on anything. ;)

tell the truth it is not what you say but,how you sat it.

Chalk it up to when she's moody, she forgot to take her Prozac for the day.

Just let her be nice when she's nice and distant when she wants to be a work friendship is different to real friendship work friendships are just a way of getting through the working day and enjoying it.
Don't confuse the two.

It sounds like she has problems with how she feels about being a manager and being a friend.
It's hard but you can be a friend and a boss as well.
You should talk to her about what you have noticed with her. She may not even know she is doing this.

Next time she shuts you out, act concerned and ask if she is okay. She will then give you the answer you are looking for herself. Could just be that she gets stressed. Maybe she doesn't realise how her behaviour affects you, so at least if you ask she'll know you're bothered about it.

Good luck

Keep it professional. u may have to ask her w? goes on???