Human brain has limitless capacity but needs rest for rejuvenation. People usually follow their hobbies to reduce stress and feel refreshed.
The time you have for yourself is very important. You can utilize it efficiently while trying to eliminate fatigue.
Passion: you did+learned+enjoyed+feeling great.
Distraction: you did+learned+enjoyed+feeling regret.
In simple words, you enjoyed an act, found it useful and want to do again and again. This is the passion.
On the other hand, you enjoyed your act, want to do it frequently but every time you feel regretful for wastage of time. That means you are distracted by this work.
Hence, think about the result/lesson of your work and try to utilize your time wisely.