AnnaStrophic's post abt 'caretaker' and 'caregiver' set me thinking abt this one...
Isn't it strange that 'carefree' has a positive connotation, while 'careless' has a negative one? In the gradation from 'careful' onto 'careless' and then finally 'carefree,' wouldn't one expect a similar gradation in their connotations too?
Any others like this one?

On second (actually additional) thoughts, '-less' is supposed to connote 'freedom' from something in certain cases... eg. clueless ;)