I am not sure I've ever had the flu. Haven't had a severe viral illness in decades. Wouldn't want to say I remember well further back than that.

Were those actually tested to prove they are a flu virus? Because typically, people say they have the flu when in actual they have a really bad cold.

I can't speak for this individual, but when kids are involved, it's normal to get tested and confirm, yes, you've gotten infected with influenza.

A year pre-covid my whole family (kids first) got the flu. Viral test confirmed one kid got two strains in succession ("A" and "B").

Its sudden onset, sudden remission, total body exhaustion, lack of my traditional cold symptoms, etc. made it very obviously different from any cold I'd had. Previous to that, I thought "the flu" was some strong "the common cold". Or just a word for arbitrary viral infection (e.g. "stomach flu").

I understand "the flu" has an ambiguous meaning now in English, but I'll certainly recognize that kind of infection again.

I'm 30 and I've only had a bad flu once. I had to take a few days off work around 6-8 years ago.