I felt this SO HARD one time!
I had to collect so many keys to open a chest to get a costume for a little pet mouse I had.
On the very last day, I finally got all the keys.
I opened the chest, and inside, I found...
I'm not ashamed to admit I rage-quit the game after that.
I missed my mouse though, so I sewed a little plushie of it. It looks... nothing like the original, but IDC.