I've been on internship since September, and I've not had this feeling for a while. Not since when I was on vacation in August and finished reading the entire course materials for CS 458 Security! I was wondering how to get it back... reflecting back to my exam cramming days, where I'd be up till 3 or 4 am and in a trance, studying. I thought coffee/tea/energy drinks would help get this kind of concentration, but it doesn't. This kind of concentration is rare, and magical. I think it stems from curiosity!
We (as in working people) get so caught up in living day-to-day sometimes, so much that we've lost our curiosity. This is extremely worrying! I think curiosity is the source of our modern accomplishments. Instead of believing in the past and believing in whatever took precedence, we choose to ask "why?". When you lose curiosity, people do things mindlessly - and their mind is dying for a break!
Curiosity a very really powerful concept, it being the source for other things like motivation and goals. Of a lesser degree is passion; nowadays, everyone puts passion here and there - i.e. "I'm a passionate coder"... to the point that the word has lost meaning to me! Whenever I see the word "passion", I think "okay, I'm kind of curious about this but not really".
Working on things that you are curious about makes you very focused, and your mind cleared. You know that feeling when you half-wake-up from a dream and your mind seems to be super quick, how your brain can process things like 100x times faster?... and you can find explanation for things instantaneously, but somehow unable to retain the information for even a minute after you wake up to try and write down what happened? Yeah! That's what working on your curiosity feels like. Enlightenment. Ethereal. Serenity.
I recall when I was young - just thinking about my future as a physicist would give me the shivers and goosebumps, and I'd just feel so good about it, so excited. I've yet had that kind of experience thinking about other things; despite how much I like my computer science major.
Anyways, enough for now - even though I'm "high on a curiosity" and in a trance.