Puzzle finished, work about to begin

Hi, guys!

Today there are only two days left before my surgery, and I am very worried. To distract myself, I walked the dog for a long time, and then we went to watch movies and assemble a puzzle.

Who can explain to me why collecting pictures broken into pieces is so interesting? Does our brain get endorphin or dopamine the moment we find the right piece? Because I just love to collect puzzles, and I just can’t explain this hobby to myself. I can sit on them for hours, angry when nothing works out and happy when I find the right part. But I can't think of what's going on in the brain that makes this process so enjoyable.

Anyway, here's what happened: