It's important to remember that one's success is measured from where one starts and everyone's challenges are personal to them; therefore, they should not be judged by anyone else who does not understand what that individual has had to overcome in their training especially when it comes to children in gradings. A grading rewards progress and that progress is individual, students are never compared. All frustration comes from comparison. Parents should never compare their children to others in a grading as you do not know the background of someone else's child. Parents who train and have their children training never criticize others' children because they know how hard a grading is in the first place. People react differently to pressure situations, and until one gets in the water to really know, they should not comment. As the saying goes: "do not judge lest thee be judged."
The grading is an assessment not a judgemental process that allows students to find themselves within the process and this can sometimes take years. Yet many want their 3 and 4 year olds to act like they are 10; it is unrealistic to expect such results, children need time to experience and learn in micro steps. In time, if allowed, amazing things happen so patience and tolerance are necessary along with trust in the process.