For example, noble prize winner, English scientist, Sir John Gurdon was the first person to clone an animal from a single cell. I mention this because his Biology report from Eton said “I believe he has ideas of becoming a scientist. On his present showing this is quite ridiculous; if he can’t learn simple biological facts he would have no chance of doing the work of a specialist, and it would be a sheer waste of time, both on his part, and of those who have to teach him.”
Okay, it's only one example but it's a good one. Mind you, there are risks in making any statements as the following school reports/comments demonstrate,
Charlotte Bronte: “She writes indifferently and knows nothing of grammar.”
WB Yeats: “Only fair. Perhaps better in Latin than in any other subject.”
Albert Einstein: "He will never amount to anything"
Robert Graves: "Well, goodbye, Graves, and remember that your best friend is the wastepaper basket”