I'm coming down with something after sitting next to a colleague with a dreadful cold last week.
My job doesn't pay sick pay, but does encourage people to work at home when they're unwell. This decreases the chance of them passing on germs to others and is more comfortable than the office.
Despite this, a colleague decided to come in sneezing, coughing with a sore throat etc for the whole week. They probably think it makes them look a good employee, but some of us have caught whatever they have already.
AIBU to think she's selfish? As I said, working home while feeling under the weather is perfectly acceptable for us to do.