Teachers should applaud students for any grade if they studied hard.
Parents should encourage their children to develop any new skill they're interested in. Doing this will make them learn the skill of learning. Which will also help them back in the classroom.
The advice of Carol Dweck, professor of psychology at Stanford University, to develop a growth mindset. Hierarchical cultures create and foster fixed mindsets, it's about efficiency, effectiveness and central or delegated authority. The complex and dynamic environments of the 21st century require us to activate our growth mindset, creativity and distributed authority are now decisive.