A kitchen sink. Did an impromptu kitchen reno due to a gas leak and being without one is such a huge downgrade in quality of life. I was washing dishes in the bathtub nightly and it was absolutely miserable. I don’t think I’ve ever been more appreciative of the technology of modern plumbing than the day I was able to rerun lines to the sink area and get it all going.
Nothing stopping everyone else from having a posh wank now and again.