I also know them feels
When our daughter was born a couple of years ago, the mother in law came over to help out for a week. Had just finished the new ensuite in the guest bedroom and all was pretty tidy.
By about the 4th day, I didn't notice (cos guy) but a bit of tension had built up between the wife and her following a minor argument, then while we were all getting ready to go to a friend's place for tea, the sh*t literally hit the floor while she was having a shower....ie. borrie paper and its contents had started squeezing up through the shower floor waste.
Safe to say that relations reached an all time low.
Took a lot of mucking around to work it out, but long story short, the plumber had teed the waste for the new ensuite into the waste from the sink in the garage. No issue there, but turned out the original owner/builder or his plumber had done a bit of a shonk and run the waste through the slab, aaannnnndddd... just stopped right there, in the dirt. Ok to handle washing out a few paint trays etc, but a few days of showers, sh*t and piss....nup.