I believe that there's no such thing as lazy.
No matter who you are, there will be something that you love
doing and able to come up with motivation.
Such as watching movie or playing games. Where did the motivation
comes from? It is just about whether you know how to channel your
motivation.
And by the way, your grades in school is not going to determine
how successful you are going to be. Grades are just a passport for
you to enter into the working world. You should be the one to define
yourself.
