It was maybe 30 years ago my wife bought me a Lee Progressive loader, I forget the model. I had ben doing all my stuff on an old RCBS Rockchucker and an old Lee O press so this was my first foray into progressive. I get the thing all setup primers, powder, brass and away I go with 44 Magnum. Next day I take my Model 29 to the range. The first few went real well and then a pop. Bullet now stuck in forcing cone.
I go see my friend Emery who is working the range. Wood dowel and rubber mallet. I tap the bullet back into the case. skip that and Bang! OK, back in business I return dowel and mallet. Two bangs later and pop again. Back to counter, dowel and mallet again. On my 3rd or maybe 4th trip Emery just told me keep the dowel and hammer.
Took weeks for me to live that down. I had been loading just fine for 18 years right till that press. Likely 1/3 of what I loaded (50 rounds) were missing powder. Still have the press but can't recall ever using it again.
I haven't done very many dumb reloading mistakes but have you ever seen what happens to a .357 Magnum case when you run it into an expander die adjusted for .38 Special.
Pulling bullets, grabbed the wrong powder jug, dumped pistol powder into a rifle jug. Had to toss about 1/2 lb powder, not a good day. Won't make that mistake again...