@saddy hi
Well that is unfortunate to hear and I am sorry that you missed out on that pie. I guess perhaps your friend did not realise you wanted the pie, hence why they gave it to someone else and why those other friends did not ask you about the pie as they assumed you must have not wanted it either.
I guess if you don't speak up about wanting something, other people will naturally assume that you do not want it, they won't necessarily offer it to you or ask if you would like some.
This is where sometimes you need to verbally communicate that you would have liked the pie to your friend, thus she may not have given the pie to the others. But you also have to remember that it was'nt your pie to begin with and that your friend is free to give the pie away to whoever they wish and that is not always going to be you.
You can't ever assume someone is going to give you something or share something just because you like it or are friend's with them.
Your friend did a nice thing in offering the pie to someone else to eat instead of wasting it or putting it in the bin.