@LaurieStrode
Wow, that's cold.
It never occurred to you that your mother might have liked to share the event with her longtime close friend, so they could reminisce about it afterward?
The people you invite are more than spectators to your big Princesse Day, you know. Some consideration for their experience is in order.
I completely agree with this. It's very self centred and also short sighted. I think it's a generational thing and younger people are more selfish and tend to be all about inviting who they consider are their friends to celebrate with them at their big day. It's also not just about the parents wanting to share it with their friends, its about the close friends who irrespective of how the children feel, are likely to be people (like the OP) who has known the child their whole life, paid attention, been interested and feel like an 'aunty' or 'uncle' in that wider sense of the word.
If you look at guest lists or photos for older generations weddings, there are typically lots of friends of the bride and grooms parents there who know the children. Admittedly that is partly because historically the bride's parents would be the main payer but it's not just that - it's a shift in values and attitudes.
If you think about it, the chances are if a person in their late 20s or early 30s invites "their mates", the overwhelming probability is that in 10 years or 20 years time, they won't even see half of these people or still be in touch with them. They will be 'friends of convenience' wearing a mantle of 'good friend' that is shed when they move away or don't work with them any more. On the other hand, the parents' longstanding friends, who've known you since you were 1,2,3,4,5, etc, will probably still be around and interested in you, even if you don't give a tiny rats ass.
Something else I'd add is that when your parents die, you will hugely value contact with their longstanding friends who will keep them alive in their memories of them. If you are grieving, there is nothing more comforting that having a longstanding friend of your parent, reminisce with you about the friend they loved. It's not necessarily the best thing to just assume these people are nothing to you, even if it might feel like that today, it may not tomorrow.