I guess this is something related to 'interest'. In my case, I study thoroughly subjects which I love (Mathematics, Basic/Advanced Electronics, Digital Electronics, Microprocessors/Microcontrollers, etc.) For rest other subjects which are related to communication like Electronics communication, Digital communication, Antenna,etc. I study before 5 days of exam, because it doesn't interests me at all. I do it just for sake of result.
If a project/work/subject doesn't interests me, I procrastinate. And I keep procrastinating to the day that if I won't work on it, the outcome maybe disappointing.
I am not a smart guy, hence I don't do smart work. My only purpose is to learn each & everything of 'Integrated/Embedded Electronics'. I really don't care about 'Communication Electronics'.
Sadly, there ain't any branch like 'Electronics & Computer Engineering' where they teach Integrated Electronics & Unix based system/embedded programming altogether.
However, there are times, when my motivation to study hard is :