I see there are a zillion replies but wanted to add my 2 cents worth anyway. When I was taking a teachers sewing class the instructor told us to snip the top thread when we were ready to change it and pull it out from the bottom, the reason being our tension runs from top to bottom, if we pull from the top, which I had been doing for over 30 years, we were going against the tension of the machine and if we had a quirky machine we could completely throw off the tension, not an easy thing to readjust. I'd never had a problem but it made perfect sense to me so now that's how I take my top thread out and it is what I teach my students to do as well. I feel more secure knowing I'm not pulling against the tension on the new computerized machines because I can't service them myself like I can the mechanical machines.