It's amazing, isn't it, how sometimes a man's fate hangs on a seemingly minor point! How many students have lost precious mark I mathematics or accounting due to placing decimal in the wrong position or omitting them altogether!
Others have failed English Grammar examination because of consistently leaving out definite or indefinite articles before their nouns, such as "the ", "a/an".
One common mark of the great performers is their attention to details. They keep working on their deficiency until perfection is attained.