I've done the influenza vaccine a few times. Once was my final year in university and they were predicting it would be a bad year. I didn't really want to mess up that because of the flu. I've also taken it before when I have sick relatives and I need to visit them in the hospitals a lot.
These days I don't bother because with everyone wearing a mask and being extra cautious, I haven't been sick at all for 2 years.
The unusual one in Korea is Japanese encephalitis. It's mostly a legacy of the past in here, like malaria or TB. The vaccine is scheduled for kids because parents worry. I've heard it's quite bad if you catch it. I never bothered getting it because it's quite expensive for adults and it's from mosquitos, so I'm only putting myself at risk.
I'll get my booster shot in 2 months, Korea is really strict with vaccine mandates. My wife is an anti-vaxxer and she can't go to restaurants, theatres, museums, etc.
I like to make fun of her by quoting the silliest reasons to avoid it that I read on the Internet, usually the conspiracy theories lol. However, she's pregnant so I'm not going to pressure her to make medical decisions.
Sometimes we have to make individual decisions with what makes us comfortable, being pregnant I agree with her to wait as nothing is ever totally reliable whichever way we go.
Go safely with whatever decisions you make.