I am in the older generation category, and living with my adult children would be the best way to destroy our good relationships. I've seen it done with mainly Italian families around here but they often have a separate apartment for the elder, or adult child so they're not sharing kitchens, bathrooms or living areas. That could work.
What I would like would be to live down the street from them, or around the block, so I could help with babysitting. One rule I have now, is I never visit without calling and checking it's ok.