Is it really that difficult?

K, so it's spring break and all the kiddos are home from school.  Gave them each one chore.  Each one is to clean a bathroom.  There are 3 kids here ages 12 (girl), 14 & 15 yr old (boys).  We have 3 bathrooms.  Do the math, one each right?  Now take into consideration that two of the three have been trained multiply times on how to do this chore to our satisfaction ~ummm CLEAN.  Not really high expectation here, just CLEAN.  They have been taught to clean sinks, mirrors, facets, bathtubs, toilets, all around the toilets (umm boys don't have good aim, still can't figure that out!) ya know, the basic stuff.  Not a difficult task, but evidently it is.  Me to kids:  "did you guys clean the bathrooms?"  Them: "yep", Me: Okay, I hope they are clean.  Them: oh they are, we know how you are about them.  Ahhh.......maybe just maybe they finally get it.  NOT!!  I totally avoided checking them because I just knew, so I let it go, until I had to go to use one of them.  I've only been in two of them so far and this is what I find.  One of them I guess decided that it was enough to clean the outside of the toilet and just skip the INSIDE.  Really?  Not to mention the soap drippings on the sink that were clearly there before the chore was assigned.  The other bathroom, well let's just say, we wiped off the countertops (not even gonna try to figure out with what) and just didn't think to even clean the sinks!!  Really?  Don't even want to go downstairs and check that one.  Grrrr.....  I mean really?  How hard is it?  There is hair and toothpaste in the sink and we just skip it?  Not to mention the streaked mirrors from overuse of windex.  Guess what?  They get to now clean them all over again today.  So how long should it take for a young adult to be able to learn this skill?  They clean their rooms just fine.  So frustrated. Just sayin........it's not rocket science.