(FORTUNE Magazine) – Phone calls not returned? Faxes left unanswered? Appointments showing up late? Today's office manners, it seems, have become just horrendous. Why all the incivility? After a decade of corporate downsizing, it may be that today's busy managers simply don't have time to be polite. Letitia Baldrige, who was Jackie Kennedy's chief of staff and who now lectures on business etiquette, thinks that's a thin excuse and points to another reason: ''Mom and Dad aren't teaching anyone to do anything right anymore.'' What should parents have taught their kids? When FORTUNE called Miss Manners, a.k.a. columnist Judith Martin, who like Baldrige writes extensively on office mores, it took her 24 hours to return the phone call. Baldrige says that's acceptable, but ''if you return a phone call or fax after 48 hours, it's horribly rude.'' More advice: Nancy Friedman (a.k.a. the Telephone Doctor), who has built a $2 million business teaching office etiquette, recommends that people always answer the phone with their name, never begin a sentence with the word ''no'' (which she thinks conveys total rejection), and never say, ''Just a second, I'll be right back,'' as this almost always proves inaccurate. And showing up a few minutes late to a meeting is unacceptable. Should this happen, Baldrige recommends the following: ''You say, 'I do apologize; it was unavoidable.' Excuses take up time, and no one believes them anyway.'' -- J.R.