I have always kind of enjoyed jigsaw puzzles. And sudoku. And crosswords — though part of the enjoyment with the latter ins having cross words for the people who write the clues. I think it’s something that resonates with my (our) “hunter gatherer” genetics. I have a friend who does them jigsaw puzzles upside down on a piece of class, then covers the finished one with a panel and turns the whole thing over to enjoy the picture. I’ve seen an ad for individually made jigsaw puzzles — they’ll even use your image — that on request can be made so there are no corner or edge pieces. And for an extra price they will NOT throw in two or three pieces that don’t fit anywhere. Uses thin plywood for the back. Several $100s.
Worst one I ever did was a Jackson Pollack painting that was to be made into approximately a 2 foot circle. Finished it during my two week Xmas break when I was in college.