I imagine, in most cases, the answer to this question will depend on whether it is from a male or female perspective!
"Man flu" is a colloquial term based on the idea that men respond to symptoms of the common cold so exuberantly it is interpreted as the more severe and life-threatening influenza. Possibly they do it to get attention from loved ones. Descriptions of classic symptoms of this common affliction range from inability to move off the bed or couch (whichever is nearest the television) to the more serious “losing the ability to do anything except groan in agony and claw at the uninfected”. But is there any scientific evidence to support its widespread use in popular parlance?