Poor misunderstood No. It's associated with selfishness, with disobedience and disrespect, with impatient inflexible uncooperative people and difficult toddlers. It's assumed to be on the Dark Side of a duality on which Yes resides with sunshine, popsicles and all other Nice Things. So, Yes is good because when someone says Yes they're saying "I will do this", "I will make room for that", "I will give this to you". No is bad because of all the things we see people not doing, not making room for, not giving. It's harder to see that the No we hear is simply the other side of a Yes said to something else, something that might very well be far more deserving of that person than we are. That if we really want to nod to the important things in our lives, it's going to have to be a sideways shake to everything else.
I've found that most of us have a severely maladjusted sense of who/what deserves which answer, especially if we grew up with parents whose lives regularly said Yes to more work and No to spending time with their families. Or Yes to anything that would take us closer to being the Perfect All-Singing All-Dancing Plate-Spinning Excellent In All Areas Child and No to allowing us space to occupy this earth as our unadorned little selves. But childhood is far behind my generation now and life constantly lays a fresh multiple-choice question before us, with only two options. It could be time we learnt to decide for ourselves, instead of letting our families and pasts pencil in the answer on our behalf.