Plant floor Leaders - giving praise

With the plant floor leaders we are coaching (a.k.a. supervisor) it is a real struggle to catch someone doing something right and giving them the appropriate feedback praise. I have told them to use the One Minute Manager five penny approach. The one floor leader reported that he was thinking of praising someone as he drove into work, he did praise them then the day's challenges surfaced and he forgot all about praising. Why is praising so difficult in US businesses? How else can we break this trend?