A Simple Concept Really

I told my 6 year old niece Mary Mayken to go and get dressed.  I gave her 20 extra "piddle" minutes figuring that it would take me 5 more times of instructing her to do so.  I came out of my bathroom and she was already dressed and had her teeth brushed.  And was cleaning up from where she brushed her teeth.  Now if a 6 year old can follow those instructions, why does it take telling my 10 and 13 year olds 5 times at least to get dressed.  It's a simple concept really.  Ask them to do something and they should do it, right?  I think that the boys need some lessons from the 6 year old!