I too learned this when I was introduced to my new Janome. The owners' husbands of my favorite quilt shop took all the Janome classes when they became Janome dealers and one husband, Bob is the guru of Janome repairs and instructions. He told me you should always pull the thread thru the needle because that's the way the thread is suppose to feed thru the machine and the machine's set tension can be disturbed if you pull it against the mechanism. Makes sense to me and after looking Bob in the eyes while he stressed the importance of unthreading, I've never pulled it the other way.