Why do some people develop severe adverse reactions after being 'vaccinated', while others don't?

There is a reasonable explanation for this: Genetic Sequencing. The most serious adverse vaccine-related events will probably occur in those groups of people who lack certain genes or who have some form of genetic abnormality or gene deficiency.

Yet people are simply getting vaccinated without any kind of testing for gene deficiencies or abnormalities. Taking the vaccine without having any adverse reactions will eventually kill you later on in life, but focusing on the serious adverse reactions we're seeing right now is deflecting attention away from the unforseen long-term effects.

Taking the shot is a bit like playing Russian Roulette as your own unknown genetic sequence will be loading your gun with live bullets. It is a shot in the dark. It is your choice to play or not to play.