In the clinical trials fever was recorded in about 15% of people that's a common side effect not rare. Chills is a side effect in 1/3 people. Significant fatigue is a side effect in 2/3 of people. So if all the people you don't know had no significant effects they are lucky.

Not sure if I can posts links still, but you can find my source by searching Pfizer-BioNTech COVID-19 Vaccine
VRBPAC Briefing Document

It's the document listing the side effects of the 38,000 person trial of Pfizer.

But, mostly ya I wouldn't call 15% rare. Also a more severe reaction to the vaccine is more common the younger you are, not the older. Opposite Covid according to the Pfizer vaccine trials. So being younger and healthier is not better in this case your immune system reacts stronger and more quickly. Rather than the slow burn of being older with a weaker immune system.