Procrasinating on an assignment can lead do a very dangerous habit. Leaving work unfinished and being happy with is a horrible habit
Most of the time procrastination stems from boredom and wanting to have fun instead of working. However if you leave work unfinished then you will be more stressed the longer it goes on.
Listening is a very important aspect to being successful, if you stay focused on the teacher when they are giving new information then you won't be confused later on
Even if you are uninterested in a class it is important to still stay focused on it. If you have all the information the first time then you won't have to worry about it later.