There are lots of threads on what you should do to build, expand and maintain a website. A lot of that is really obvious, some are general good ideas but sometimes we risk ourselves killing a website with what it seemed to be a good idea, just because readers won't always react the same way, and SEs are not people.
So, any stories of something "good" gone wrong?
#1. Redesigning a website. Sure, keep it fresh, do it right and as some old threads said "redesign from time to time". Well I had one website with good traffic generating good income, too simple, an ugly duck. So I decided to bring a new design with all the traditional checklist points: clean, valid html, usable, redirects, etc. Despite the site being what I would have done from scratch on a new project... everything went wrong and traffic vanished. I never figured out. Later I tried another redesign, a fast site with new, fresh content keeping what I already have. Same result... So the site stays at this day with the same simple old design.
#2. This is not mine, but from the company I worked for. They decided to buy a BIG webserver to config everything from scratch aiming for speed and low cost as the overall result. Everything went wrong!. Then migrated the sites to a couple of servers. FAIL. Then everything to a new BIG server: worse!. Their OLD idea of building all the minor sites (with not so high traffic) into "X CMS" (won't say the name) sounded perfect but it became a nightmare (for them). Since then the traffic of all the websites went to another planet... Oh look at all the money they saved! (some offers allowed 30 days money back guarantee, some didn't)
What about you?