I was just thinking the same thing... We have lines of commented out code from 1988 (yes. that is a correct date) that people flat out refuse to delete. I am so glad I got out of that mess...
And when reading somebody else's code, I tend to appreciate if the code carries its history with it, at least to a degree. What I really do not like, though, is when there is a piece of commented-out code with no explanation of why it's there in the first place or why it was commented out.