“That other boy did better than you on the test”
The majority of parents have the very best intentions. They might often say to their kid something along the following lines: ’Don’t worry about it, the same thing used to happen to me, but look, I turned out fine.’ They say such things because they can forget how upset they were when their parents used to tell them off, or chastise them for not being as good as others. The latter in particular (’why did she do better than you on the test?’) can be a very painful experience which children carry into adulthood. They end up hating the person they were always compared to. A child intensely dislikes being compared to others, be it their classmate, sister or brother. As adults, such people will continue to compare themselves to others — and this is never a healthy thing.