[Jtsummers]

Not with startups, but I'll admit to this fault for myself with technical content. I spent (I won't say wasted, I enjoyed it) a lot of time learning more theoretical areas of CS and software engineering without a need to apply it. The breadth of knowledge has proven useful in general, but often long after the reading and required some effort to relearn and apply properly. I would've been better off with more of a survey of the same topics (which could've meant surveying more topics in the same span) and then learning the details when I needed it.