This one simple phrase can mean so much! It can mean, she's so ugly - bless her heart! Or she's so sweet - bless her heart! Or she's naive - She's too in love to see that her husband is keeping all the whores in town in high heels and lipstick! Bless her heart can be used for so many different things that I believe it to be the the most "Diplomatic" phrase in the entire Southern Girl's Dictionary!
One meaning is: (to waste time, money etc.) To spend time in a wasteful, trifling or ineffective way; dawdle. (He wasted the day piddling around.) OR It was a piddley amount, meaning it sure wasn't much.