https://www.forbes.com/sites/alicegwalton/2017/12/12/man-flu-may-be-an-actual-thing-study-finds/ Personally I had never even heard this phrase until a couple years ago. Working on a nearly all-female team, when I returned from some sickness and told them how I felt like s*** and couldn't leave the bedroom, the females immediately dismissed it as "man flu"; that is, of me (and all men), either greatly exaggerating my symptoms or just being a p**** ass b****. This caught me off guard because 1) I really was sick (though I spared my coworkers the tales of my simultaneous vomit/diarrhea) and 2) I didn't even know this was a thing so I had no comeback. Well turns out men really do feel flu and other symptoms harsher than females. So, boom. Deal with it.