Castandblast is right. Shoulder straps stay hidden in the back pocket until used as pack straps. I put my rain jacket and a few other quickly needed items in that hidden pocket. Don't want to leave it wide open just to try and use the wide shoulder straps thru the common loops. Also, the shoulder straps are 2" wide and don't really run well thru the 1" common loop.
I also removed my shoulder straps from the guide lid and just use the bottom 1" straps when I want to carry it around like a day bag. Works perfect and no need to have the extra shoulder straps permanently attached. Less mess, less weight, and just not needed with my 1" bottom straps all ready to go if needed.