I'm just coming from mine, and had a beautiful time! It's the feeling of coming home, the place to feel safe, get advice and wisdom and feeling cared for. The place of unconditional love.
And we may get this in different places. Some of us get this mostly or solely from our birth parents, some from our adopted parents, and some from different sources at different times - this is where the aunties and daddies without human children or with less children they envisioned come in, the neighbors with an empty nest but lots of wisdom, and those people who may or may not have their own children but who double as fathers or mothers for dozens, hundreds, thousands, or even millions of others, and for others it is God - and that's a beautiful thing - it gives the birth parents a break when they deal with their own stuff, and it's the village most of us don't physically have anymore.
Sometimes, it can even be a stranger who comes out of nowhere and gives just the right advice - parental figures can be found in many places, and there is one beautiful German word that describes the feeling best, I think - Geborgenheit.
It is something to be immensely grateful for - we may not always feel it, sometimes we may sorely miss it, but you can only miss something you already have a concept of - so if we look closely, all of us have had it at some time in our lives when we needed it the most.