Basically, with Reagan, they always knew where they stood and understood the boundaries of behavior which would have consequences. They would go right up against these boundaries but not cross the line.
With Carter, they could do something major and there would be no consequences one day and the next day, they could do something far less serious and find their negotiated wheat sale canceled or the Moscow Olympics boycotted.
IOW, it is much the same way a teenager prefers a parent with clear rules to one who wants to be your best friend and is inconsistent.
I heard that also from an elderly friend of the family. The peanut farmer drove the Politboro so nuts trying to figure out where he stood on any given day much less in the future that arguments resulted in at least a couple high-ranking commies getting demoted or shot out of pure panic that something they said or did or suggested was going to result in a SNAFU later on. Promises got reniged on, personal agendas got run over and toes were stepped on when he suddenly changed his mind and an angry cheated Commie is a force to be reckoned with.