The worst of these started when I accidentally shut the cat in the living room with the inevitable messy consequences. In my attempts to repair the damage to the sofa cushions I thought I'd take the cushion covers off so I could wash them and the inserts separately. That's when I was reminded of the most common failing of zip fasteners. They stick, especially when they haven't been used in a while, and these hadn't been opened since we bought the sofa. I took up the first cushion, seized the tag and pulled. Nothing happened. I tried again, still nothing. I may have then said a few words my mother wouldn't have approved of. I pulled again. It didn't budge. I tried my mother's trick of rubbing a candle along the teeth. Nope. Still stuck.
I examined it more carefully, starting at the tag end and moving along to the other end. The teeth were all aligned - until I got to the other end and found they weren't. It's possible there were more mother disapproved of words before I realised that the misalignment wasn't part of the problem since all the other teeth were properly meshed together. Back to the tag with a pair of pliers and a hope that brute strength would work this time - and it moved, only a few centimetres but a start, before it stopped, then moved again, stopped and so on until I finally had the cushion open. Except for the misaligned section, which blocked the opening just enough to prevent me taking out the insert.
More muttering. I decided to turn to the next cushion and found myself in exactly the same position with a jamming, misaligned zip which I could only partly open. At this point I gave up the battle and washed both cushions as they were. At least that way the water could drain out from the inserts through the gaping openings - and surprisingly, once they were dry, the zips did up with no difficulty. It was like they were taunting me.
I won't bother to outline my problems with the self opening jeans' zip or the zip up bag which has somehow managed to jam its tag underneath an overhang of fabric which can't be cut away without destroying the bag, except to say that obviously zips have it in for me at the moment.
So is there a solution? Suffice it to say these things rarely happened in the "old days" when all zips were made of metal and had larger teeth. That wasn't perfect either, of course. Metal toothed zips were bulky, prone to corrosion (I bet candle wax would have worked on one of them, though) and less flexible than our modern day zips made as they are of nylon and designed to be invisible but after, my recent experiences, I think I'd sacrifice visibility for practicality.