The workforce is not always a welcoming place for women. Though things have certainly changed, preconceived notions about what sorts of positions women hold in an office are pretty deeply engrained—as is general sexism. Most women who have encountered some pretty ridiculous assumptions from people at work, and while they're kind of a bummer when they happen, getting together to laugh about it is cathartic.
Reporter Nicola Bartlett tweeted about a man questioning who she was after she called him with a question. He assumed she was calling on behalf of another reporter, you see. A MAN reporter.