i sure have, lacon. obviously some people have a real knack for these puzzles--i'm not one of those people! i might have a bit of a knack, but not a "real" one.
i used to work and work at a puzzle, but recently i've given that up--now, after a reasonable time, i just give it up and go on to another one. that's what works for me right now--i do these for fun, not to add more stress to my life!