The most considerate thing any sick person can do, is stay home, and avoid sharing the germs with others. If a boss insists, on your presence, he/she deserves a huge kiss, right on the lips, and a couple of uncovered sneezes aimed in that direction.
Health is all we have...You got to prioritize and love yourself, and put yourself first...It isn't selfish...It's just, if you can be 100%, you cant give 100%!
