> That doesn't mean I need to understand the entire code base, but if I'm modifying a portion of the code base, I'm loath to touch it till I understand what it's doing.

This is also me. I get flack for spending too long on what seem like "small" fixes but I can't be sure (especially in spaghetti code) until I've dug through it. On a couple occasions, different companies unfortunately, I caught flack for spending too long trying to understand critical finance code. As in, how we were billing every single customer. But it always yielded results, and a week later I'm in a meeting explaining how abc original implementation would have broken xyz, but the scowls never really go away. It's frustrating.