Tattos
The subject of tattoos caused one heck of a row in our household in the early 90s when our lovely daughter came home and announced to us that she proposed to have a tattoo.
My wife went bananas and I fully agreed with her that a tattoo would be a major obstacle to landing a good job in later years with the result daughter did not have this tattoo.
Now she is an adult she is always saying that she's glad we forbade it at the time.