I've been pretty lucky. The only thing on my shelf is a loaded .223 round with a spent primer in it. I still don't know how I did that. Its just a reminder to double check.
One other confession--I left the primer out of one round on my turret. Noticed the powder draining out the bottom just as I seated the bullet.
That's about it in 10yrs of reloading. Good reminders to be careful.
I am Pro-Rights (on gun issues).