I love using the eraser on the back of a mechanical pencil
I guess I could say its more of a quirk. Actually, back when I was in standard 3 or 4 I've never ever enjoyed using it. I'd always use the normal eraser instead. Though since I started drawing, it started to become a habit. I guess it saves more time and all.
So, my normal eraser would stay unfinished and will get lost somewhere at school or in my room while the eraser on the back of my mechanical pencil will be finished in just a few months because I draw at least 3 pictures a day and also a lot of doodles.
There you go, a quirk! But beware whenever you lend me your mechanical pencil *grins*