Linoleum Tile
Boomers went wild and crazy with this type of fake, plastic tile. It is all over those beautiful, vintage kitchens. Half of the time, there is a perfectly preserved hardwood floor underneath so it's technically a win. Still, linoleum is a tragedy for home design.
Shag Carpet + Wood Panneling
This type of design was popular in the 70s which is totally fine, but Boomers never updated their homes for some reason. There are unreasonable amounts of homes online that are still riddled with shag carpeting and wood paneling.