I'm currently working on a team of web developers and what I experienced here so far is remarkable in a negative way. Their web application is poorly documented and have so many bugs.

The most frustrating thing is being hired to work for a poorly documented software. It makes things hard for those who take over the project. Lack of comments and poorly written semantics especially when the previous programmer leaves a bunch of bugs and errors. To top it off, the client don't want the software to be rewritten, he wants it to only be alterred.

In my situation, the client don't want the website to be redesigned as I suggested. He wants it to be mobile-friendly. I need to edit the poorly documented css at the same time adding my own code to the webpage which makes it bigger in terms of file size which should be smaller if I redesigned it from ground up. The previous dev left thousands of lines of poorly written CSS that overlaps and affects my design that's why I have to write very specific css rules. In the end I've managed to fix the problem but the file size grew bigger and page loading time suffered.