Today's leadoff letter to the Monday Morning Quarterback is from a federal manager who says he doesn't understand the flap over layoffs. He says civil servants are protected from the reality of the marketplace and says he has personally fired 11 nonperformers and "never lost a night's sleep" because of it.

Letter number two is from an Arlington man who says feds have no reason to rejoice just because the final budget approved by Congress does less damage to federal pay and pensions than budgets originally proposed by the president and the Senate. Here goes:

* "To read your column . . . one gets the impression the government shouldn't ever fire or lay off anyone. It would be one big happy family with the taxpayers footing the bill! Could any business run this way?

"I am a federal manager . . . . In 25 years I've fired 11 people and had to lay off 60 more. I never lost a night's sleep! Those fired deserved it, and had more than adequate warning. The taxpayers deserved better for the dollars than those people gave.

"The layoffs were another matter. However, I always told those departing they could go out with their heads high and prove to the world (and other U.S. workers) they could get another job. Most did just that. All they needed was confidence in themselves, which most federal workers lose once they are on the job for any length of time.

"There are too many protections for federal employes. Can you imagine someone from a scrap yard or builder's supply company (I worked for both) writing his congressman when he gets laid off? This is usually the federal employe's first thought.

"The typical fed has no self worth. Vast protection programs ensure they never need worry about losing a job except in the most extreme case.

"I'm tired of hearing about the abused U.S. worker. How 'bout the abused taxpayer?

"Your July 25 column told of a government doctor downgraded to a typist and of a psychologist who took a clerical job. Can you imagine anyone with any self-esteem doing so? I can't." Unsigned

* "People like you seem to think federal workers are relieved or even happy because all the bad things Reagan wanted to do didn't happen . . . . You must be beginning to believe the propaganda that bureaucrats are dumb to think we fall for the trick of a pay 'cut' being reduced to a pay freeze.

"It appears we'll endure the first pay freeze since the 1950s . . . . The pay freeze represents a pay cut -- or a tax hike leveled exclusively at federal workers. The damage is twofold: The loss of pay and also being singled out . . . for the freeze.

"How can you believe feds are happy, satisfied or even relieved about the budget outcome? Every federal worker I know is at the lowest point from a mental and morale point of view. I wish your columns would reflect this." M.L., Arlington

* "We have been members of Blue Cross-Blue Shield since 1955. Three children, broken bones, etc., were paid for. From 1975, when my husband retired, until 1984 we had the Blue Cross-Blue Shield high option, which took $140 per month out of his pension.

"He goes to the clinic. Our kids are grown. I have not used the insurance since the birth of a child in 1960. Look at the cash we put into Blue Cross-Blue Shield.

"Why give refunds only to current enrollees? What about old retirees who have not used Blue Cross-Blue Shield insurance for years but still paid the monthly premiums?" G.S.L., Washington