I've always hated the response "We'll see." because it ALWAYS meant NO! Growing up, anytime I asked my mother if I could do something or have something, the answer was either a direct "No" or a "We'll see" which was almost worse because I'd get my hopes up and sure enough, eventually, the answer turned out to be NO anyway.
And now my sister has adopted this habit of being non-committal. It drives me crazy! I said to her on Friday - "Next Sunday (meaning a week and 2 days from now) can you come to my house and help me with my closet (this is her birthday gift to me - helping me clean my closet). Her response - "We'll see". I'm thinking - what, do you want to see if a better offer comes along? Now obviously there are a LOT of better things to do than clean a closet out on a Sunday in July, but she uses the "we'll see" for other things too. Had I said "Next Sunday do you want to go to the movies?" the response would have been "We'll see". Just say yes or no, dammit! I've asked her why she doesn't give a definitive answer and she says because she doesn't know what might be going on then. Well duh - if there's some valid reason you can't do something we planned, we just cancel - no big deal. But nope - it's always gotta be "We'll see".
So... will she help me clean out the closet on the 11th?? We'll see!!