When you inherit a software project, the people who made design decisions and have already moved on, well they made some terrible mistakes, how could they ever

When you inherit a software project, the people who made design decisions and have already moved on, well they made some terrible mistakes, how could they ever have thought that was a good idea? And now we have to live with their horrendous mess. I've got to put so much effort into working around it and fixing it all. And I fully acknowledge that when I move on, I will be one of those people to the next set of developers!