I KNOW, RIGHT. it's this mentality of "Oh, but I couldn't possibly take any time off, I'm too important/my job is too important/I've got so much to do" blah blah blah. And what these people fail to realize is that if they are ill, they are PROBABLY CONTAGIOUS. And that means that not only they will perform poorly and possibly need time off, but that the rest of the department is at risk because ill people insist on coming in. Ultimately what could have been one person's private bout of noro becomes the entire department's two-week saga of sick-days and leaving-earlys and "I feel rubbish but I'm here because I'm just so dedicated - however my performance will suck, because I feel rubbish." it kills productivity and the company line at ANY company should be "Don't come in if you're ill".
The same goes triply for schools!! Good grief, why on EARTH would you dump your toxic child (who feels awful and probably just wants to curl up in bed) in the midst of a load of other children, thereby practically ensuring that 40%+ of his/her classmates will fall ill? This is schooltime lost for the child, work-time lost for parents who bother to stay home, teaching time lost for the teachers, and a miserable time for everyone. It is NOT a display of Dedication and High Motives to go to work when you are ill or to send your sick child to school. And it sends the wrong message to those parents and colleagues who DO opt to stay home/keep their kids home when they're ill - it says "you're lazy, look at me, I come in even when I'm v*!"
As if we don't feel paranoid and guilty enough without people making light of ACTUAL ILLNESS.