A recent report found more than 90% of patients affected by a chickenpox outbreak in New York City had no documentation of receiving a chickenpox vaccine.
Just 1.4% of cases were among people who received two vaccine doses.
People who had chickenpox as children are at risk of getting shingles in later adulthood, which is supposedly awful and very painful. There's not much to like about that.
As others have already noted, vaccination wasn't an option and parents would get their children chickenpox on purpose when they were young, because it can be much worse when you get older.
Had to look up the date of the vaccine, looks like it became commercially available in 1984, and licensed in America by 1995. If you're 30-40+, you were probably forced to have it as a kid.