The two fonts which I seem to use most often are Times New Roman and Arial.
When I underline words in Times New Roman a small space separates the underline and the characters. This, I have always assumed, is the generally accepted layout and is attractive looking. With Arial, however, the underline is tight up against the characters and results in a crushed appearance. I have noticed the same inconsistency between other fonts. Is this considered normal or is the lack of spacing an anomaly of some sort?