LOL! I hear you. Maybe I'm just getting older & wimpier, but I swear in the last year or so there's been a change in either the material or how they seal the bags for things like breakfast cereal or crackers. I used to be able to pull the bags inside the box apart at the top, opening the plastic-melt seal they use, without tearing them. No more. The melted seal at the top of the bags is now far stronger than the plastic bag itself. Might as well get out a pair of scissors (or a chainsaw :) and just cut off the melted seal right away rather than try to pull the iron-clad seal open with your hands and just end up tearing the bag up instead in the process.
I've never understood the point of the clear plastic packaging that things like low cost electronics come in. You need a serious knife or scissors. I guess they've decided they don't want people putting things back in an open package. But why such heavy material that you can't breech by hand?