[Torn]

I've seen a lot of it in product codebases (both Enterprise and Startup) I've had to work with.

I guess it's different when you're maintaining a library - you have more freedom to version up and rewrite things.

[mercurial]

Sadly, many of the "older" programmers haven't learned any better. And sometimes it's a limitation of the language (eg, Java which doesn't allow default implementations in interfaces).