Having recently moved in to a new place, I needed to unclog out both bathroom sink drains. This house was built in the 50’s and the previous owner used draino liberally, so both drain tail pipes snapped like twigs at the threads when I went to remove the trap. I tried replacing only the damaged parts, but ultimately, nothing was salvageable, as each part I replaced led to another catastrophically failing.
The guest bathroom plumbing wasn’t too bad, as the vanity is spacious and things were at least installed correctly despite the damage. The en suite, however, has a cramped vanity, is too tiny to lay down in, and whoever did the plumbing directly abs-welded the <1" wall stub to a DWV elbow instead of using a slip joint. I had to take a hacksaw blade and gently floss the pipe between the wall and the joint, taking ~45 minutes and only having enough room to use my fingers to grab the blade
The plumbing is now done correctly, uses the right parts, and will never see draino again as long as I live here.
It lies somewhere between pride, relief, and satisfaction. I understand the feeling all too well, my last house was also a 50’s build, but someone did a budget flip on it and I spent all of my 9 years there fixing their mistakes one by one. Then I moved just in time for someone else to enjoy my repairs haha.