When I was a little girl, my mother would never let me join after school activities or clubs. Her main reasoning being that, "You're not going to finish it anyway. You're just going to quit."
Considering she never let me join anything anyway, one had to wonder how she knew I'd quit before even trying. However, my mother hated being called out on stuff, so I would wisely keep my mouth shut. And after awhile, I just stopped asking my mom to let me do stuff.
In doing so, I came to believe that I would never finish anything and so there was no point in even trying. It built up this belief in my head that I was a lazy and unmotivated person. And it shaped my behavior quite a bit during my teens and early twenties.