I hate plumbing... when we built in VA. the house passed plumbing inspection when I pointed out to the plumber the drain for the tub was not hooked up. Builder wanted the plumber to rip everything out and redo it... That was a waste in my mind and I helped him splice the tub in.
We also had a backup, they cut a hole in the new concrete floor... they didn't find a problem - but it "cured" itself. I didn't have a problem with it but the builder did not speak to me for weeks about it... embarrassed about it. It's was not a problem to me, I didn't care...