Head and Heart: Why do we find it so hard to say no?

The holidays are over, but the aftermath isn't. Maybe you said yes to a few things in the moment – and now you wish you hadn't.Messages start coming in. Plans you half-agreed to suddenly need dates. An acquaintance reaches out for a catch-up. It can feel easier to say yes, just to be polite and avoid awkwardness.But that yes can quietly stretch you thin, and take time away from the people you actually want to see.Why do we find it so hard to say no? And what can we gain when we learn the art of letting someone down gently?