MIL drives me nutso!

my mother in law is the sweetest but sometimes she drives me nuts! When she watches my daughter she complains about the length of naps she takes (if she even gives her a nap!) The end result ends up being a cranky toddler come 5 o'clock cause grandma didn't want her granddaughter napping while she was visiting! I know it is a stupid thing to complain about but when I have a cranky toddler it drives me nutso!