When I had my first kid, back in 2012, I was told to get a flu shot every year by my then wife and I did for 6 years. Those 6 years, I had strep throat 4 of them and ended up getting the flu the other 2. Never had the flu or strep before then (that I remember). I'm sure my parents made me get the shot when I was younger but never did after it was my decision.
I'm not against the flu shot (for others, including my kids) but those were the only times in my life I've ever had strep or the flu is when I got the shot so I skip it now.
Some people just react differently and apparently I'm one of them.
And I probably jinxed myself also so we are both in for it.