I think we're all conditioned into thinking we're somehow better people if we struggle into work when we're not feeling great.
But when I'm lying on my death bed and looking back on my life, what am I likely to be thinking:
A) I'm so glad I dragged my arse into work on those days when I felt a bit shitty. Slogging through the day when I felt rotten was worth it.
OR
B) I'm glad I took the time off to rest and recuperate when I didn't feel very well. I'm glad that I made taking care of my well-being a priority.
Quite apart from the fact that going into work when you're unwell spreads germs and could infect others (compromised immune system or not, it's still a shit thing to do)....there's also the fact that what is it about "showing resilience" that is so important? All it means is that you didn't care enough about yourself to take time to recuperate and rest when you weren't feeling well. A heavy cold is a very good reason not to go into work.
I agree people throw the word "flu" around too easily, and I do find that irritating. But I think that's because there's a social pressure to make any illness sound terrible because otherwise people will judge you for not soldiering on.
And I say this as someone who wasn't off sick at all during 11 years in an office, apart from 2 weeks for a miscarriage. I was pregnant with twins, and carried on going in and working extra hours even though I was throwing up constantly all day long. I ended up giving birth prematurely (thankfully the DC are fine now, many years later). But I was stupid and it's taken me years to realise that there's no prizes for not putting yourself first. And for the majority of us who work for companies - rather than doctors, nurses, teachers etc - all you are doing is prioritising their profits over your wellbeing.
I've been self-employed for 13 years+ now and I still have to master the art of taking time off when my body is telling me I need to take a break. But bollocks to resilience. I'm working on looking after myself better and actually I think that's important. Everyone should be encouraged to put their health and welfare first without being shamed. We're shit at encouraging self-care in this country.