Zipper curse

I have fallen victim to a weird zipper curse. Just since September, I have somehow managed to break the zipper on:
• One very expensive purse
• One long plaid skirt
• One long black skirt
• One fancy pillow case for my contoured pillow

The zippers for the purse and the pillow case are completely non-functional, as in, they do not zip any more at all. You can move them back and forth, but the teeth refuse to connect with each other.
The zippers for the two skirts will go up, but only to a certain point, and today, the zipper on the black skirt got stuck and will no longer go up or down.

Thankfully, I was able to take it off over my head, or I would have ended up on the elliptical machine in a skirt and workout pants. I suppose it could have been the start of a new trend. I guess we'll never know.

I don't understand all this zipper trouble though. I admit the purse was probably my fault, and I suspect the pillowcase shrank in the wash. But it's not that the skirts don't fit. They are actually both a little bit too big. Have I lost the ability to use a zipper? I thought this was a technology I mastered years ago.