[Tainnor]

Both is a problem. It's just that, as a dev, you're less likely to see code with massive amounts of duplication because any mediocre developer understands why this is bad.

However, work with really bad (or just extremely inexperienced) devs and/or people who are not primarily coders (e.g. data scientists), and you'll see a lot of under-engineering to the point that it's almost impossible to figure out what the code is actually doing (especially when it's coupled with random code that is inserted without understanding, just because it makes things work somehow, at least on the dev's machine).