It's tricky to answer that question, because it turns out that some things that people think are abstract as heck turn out to be pretty useful, and I suppose it could go the other way. For example, neutrino diffusion turns out to be very useful in finance, but I had no clue that this was the case when I did my dissertation.
It turns out that "do whatever seems interesting" worked out quite well for me, and probably a lot better than if I consciously decided to do something. I'm not sure why that is.
One thing that you do have to be careful about is that statements about what is and is not useful can end up affecting outcomes. For example, suppose I told you that some math was too abstract and therefore useless. No one studies it, and what will happen is that in a few years there is a desperate shortage of people that have expertise in that exactly sort of useless math. Remember that we are talking about 1000 graduates each year, and so if 100 people make decisions based on predictions that could flood the market or create a shortage.
I suppose what people are asking is someone to tell you to "do X or don't do X", but markets perversely adjust to counteract any sort of advice that you give.
Curiously, manual labor does have a lot of respect in my neck of the woods.
Except that in the end both of you are going to likely end up shuffling papers for some large corporation. Most people that major in things like art history or Russian literature don't actually end up doing anything that have anything to do with art or literature.
But I think it's better to be educated and miserable than uneducated and miserable.
I think it is true. Also, money *does* buy happiness.
I'm seriously, seriously skeptical of this. If someone that has an associate degree comes online and tells me that they are having no trouble finding work, I'll change my mind, but one thing that bothers me about hearing about the wonders of technical education, is that I don't hear that many real live students that say this.