did you ever study unuseful things?

I'm just being bored here by my 'Empirical studies in economics', which has nothing to do with my own major, as I've never taken advanced mathematics and applied statistics in college so the econometric stuff is way too difficult to me. The only reason I chosed this course is the teacher did mention in his syllaby that advanced mathematic skills is required. I agree that no knowledge is waste but here my case is that certain fundamentals are necessary for further studies on a subject. But, ye here your questions are little bit far from your title of the post. I never regret 'cause I used to have excellent academic performance in school.

Yes. I had to in high school and I hated it. I had to learn Geometry and none of it made any sense to me. I never did learn it and the teacher never tried to teach it to me either.

what is useful or not useful? I LOVE history, but how useful is that? I minored in history, I have continued to learn about history even in the 30+ years since I left college. On the other hand, probably math might've been a good thing to learn, but I can't learn it so I haven't bothered.

Well when i like certain subject to be learned i just learn it i think knowledge is never waste it comes to use some other day in some other way.so i dont think there is anything that you learn is useless every small good thing we learn has some meaning and use.