A good deal of the current discussion of vaccination takes it for granted that it is in almost everyone's interest to get vaccinated, hence that failure to get vaccinated is evidence of false beliefs or irrational behavior. To see why this is not true for everyone, it is worth looking at some numbers.
According to the CDC, the estimated infection fatality rate is 0.05 percent for 18-to-49-year-olds. I start my calculations with someone who is certain to get infected and has a life expectancy of thirty years. Thirty years is 262,800 hours, so the reduction in life expectancy is .0005x262,800=131 hours.
If you believe your chance of getting infected is only .1, not unreasonable if you regard the current wave as the last of the epidemic, that reduces it to 13 hours. If you are 25, which according to one source gives an IFR of .01, that takes it down to less than three hours. Saving that may not be worth the time and trouble of two injections, a likely few days of not very serious side effects and some small risk of more substantial side effects. The same is more true for younger ages or people in particularly good health.
It may be objected that a .1 probability of getting infected is unreasonably low, but that depends what you believe about vaccine effectiveness. If you are optimistic about vaccines, you should expect the current wave to be the last serious one. If you are pessimistic about vaccines, the risk of infection is much higher but the benefit of vaccination lower.
It may also be objected that I am looking only at death. I don't have, I don't think anyone has, good data on long term effects of getting Covid and recovering. The short term effects range from zero for asymptomatic infection to several weeks in the hospital for almost lethal infection. Including that would reduce the number of people for whom vaccination is not a clear benefit but not, I think, to zero.
And, on the other side, I am ignoring people who have already had Covid, hence have protection comparable to, perhaps better than, that provided by vaccination. Vaccination apparently increases the protection, but not by much. The CDC estimates that about a third of the population have had symptomatic Covid, so that is a large group for which the benefit should be reduced by at least an order of magnitude.
I am 76, so a similar calculation implies that I should be vaccinated, and I am. But I do not agree with the claim that everyone should obviously be vaccinated as well.
All of this is in terms of the self-interest of the individual. Vaccination also reduces the spread of the disease, benefiting others, although by how much is not clear. That is an additional argument for getting vaccinated but one whose size is harder to estimate.