As an immunosuppressed individual, I HATE when people come into work sick as it means I have to go home. For me it's gastro stuff especially, despite having several memos going round at my work people still insist on coming in when they've been up all night vomiting out both ends!
Colds and sinus infections etc fair enough, but if you suspect you have the flu/bad infection then please don't struggle on into work just to make a show of how brave/committed you are.
I also hate the working culture for forcing people to attempt to do just the above, no one should be penalised for being sensible and staying at home.
Last time someone came in sick I spent 2 weeks in hospital after catching their gastro bug.
And as to the mns saying you can't have the flu and be online... YABU.