I was discussing with a workmate whether user interfaces should be phrased in a positive or a negative manner. I've observed positive sentences are clearer than negative ones to the average user.
I've heard some discussions on this matter and most people seem to agree that phrasing positively yields better results in user experience than negative ones. But is there a UX recommendation on this?
EDIT:
to be clearer: should I notify my user that his/her input data is invalid by saying "input is invalid" or "input is not valid"? Or does it not affect UX at all?
Is it better to negate a positive verb or use a verb that has a negative meaning in itself?