My guess is the side effects of the vaccine, the low effectiveness of the vaccine, and the relative rarity of the flu combine to make it a genuinely questionabl

My guess is the side effects of the vaccine, the low effectiveness of the vaccine, and the relative rarity of the flu combine to make it a genuinely questionable choice for most healthy adults -- I get the flu vaccine annually now in an abundance of caution (I have an immunocompromised relative), but prior to that I went more than two decades without getting the flu vaccine and did not once get the flu. Since the vaccine itself reliably makes me feel miserable for 1-2 days and the flu makes me feel miserable for 1-2 weeks I came out substantially ahead. Not saying that's necessarily the right choice from a public health standpoint, etc; just providing my anecdotal experience.