[JohnFen]

I think it's a difference in approach and goals. One approach isn't better than another -- it all depends on the person and what their overall goal is.

Personally, I've found that very often, things I've learned that were apparently unrelated to the task at hand gives me a key insight in how to approach the task at hand in a better way. That broad knowledge base is a large part of the value I bring to the job. This continuing education is not limited to technological topics -- any knowledge from any domain may be useful to me as a dev.

This is why I go out of my way to learn things as deeply as is practical, even (or especially) if that knowledge is much more than what I need for the immediate task at hand. I'm taking a natural opportunity to advance my overall knowledge and skillset. The immediate task at hand is only part of what I'm being paid to do. Another part is expanding my knowledge base. A huge part of what I want out of any job is to expand my education.

Other devs don't have that as their goal, and there's nothing at all wrong with that. It's just a different style and different overall goals, is all.