Why are people so stingy these days?

I invited some friends over for a holiday and I made most of the food. They all offered to bring either a side or dessert and I was very appreciative. Two people decided to bring their sides back home after the party ended…I was shocked! Who brings food to a get together and then brings it back because it wasn’t finished? Considering I spent way more money (rightfully so, since I hosted) on the bigger stuff for everyone I feel like it would have been a nice gesture to leave me some leftovers. Am I crazy?