Sometimes, everything is fine as long as you say 'OK' to everything.
The moment you said 'No', all that was OK a moment ago - vanishes in the blazing flame of hell rage.
Why? Are you expected to say 'OK' even if you think 'No'?
Why is a single 'No' unacceptable in the sea of OKs?
Do these OKs evaporate suddenly?
Or maybe, this single 'No' just becomes an iron spike in the eye of a selfish one, making him/her blind to see and appreciate every OK you gave before?
That is not OK.