If you are lucky, all the pieces are there. If not, you could be searching for missing pieces and feeling like the puzzle is incomplete. If you are luckier, there aren't pieces from another puzzle tossed in amongst the others. That really confuses things. Tear it back up and dump in back into the box for another day.
Puzzles are never the same the second time around.
Or you can glue the pieces together for prosperity - but no one could really appreciate the trials you went through to put it together. Well, maybe your mother. But then she'd love anything you made, even a bumpy picture of a jar of jelly beans, and that's life.