Everything crooked can be fixed with museum putty - well, not everything.  Museum putty (aka quake hold) is known for being great at keeping collectable steady on shelves, but it is also a quick fix for crooked pictures on the wall.  Frames get knocked out of place, are sometimes unevenly balanced, or the nail/hook just isn't in the right spot.  Place a little ball of putty in the bottom two corners of the frame, and press it to the wall to secure.  Now you're straight as an arrow.  Next step... Invisalign.  This is one more way to Pull It Together.