It is
so simple to unravel it neatly

, thereby leaving the
whole bag available for gathering rubbish, instead of wasting the top inch which you have ripped off in your impatience.
Place the bag with the single line if stitching facing you, ie the side where the stitching looks like this:
-------------- not the side with a double line, a bit like this: =========.
Then go to the right hand side of the bag, look over the top and pull a single end thread from the double threaded side. Sometimes it will unravel imediately, but quite often you have to fiddle to free the end. It is actually done in a chain stitch so once you have freed the end and pulled, then the bag should open all along the top.
You can
only pull the thread to open from the right hand end of the bag and starting from the side away from you , while holding the bag as described above.
Alright I know some of you will still rip it apart in your impatience!

But trust me, sometimes with a bit of fiddling, sometimes without, this will always open the bag in a neat and orderly fashion.