C'mon guys, if you have never made a mistake, then call the rest of us names.
I have:
Set the powder scale wrong
Used the wrong projectile
Used the wrong powder
Over expanded the cartridge case
Thrown double charges
Loaded bullets into cases with no powder
Dumped a bottle of powder on the loading table and floor
Dropped several boxes of primers
Tried to load steel/aluminum cases
Gotten cases stuck in my die
Set my seater die wrong
In each situation I discovered my error because of something you guys said here on the forum. I stopped what I was doing and asked questions. I have five reloading manuals and I go online to check powder charges and bullet types. (I learned that from you guys, Thanks.)
Will I screw up again? I guarenteeeeee I will. But, like Mike, I hope I will continue to realize when I do something wrong or realize something is not right and I hope you guys are here to help me out when I do. (especially when I decide to start reloading shotgun shells.)
Mike: Like they said above, just check the brass before you reload it.
While I was getting my reloading stuff together, I picked up a lot of brass. I did not know there was a difference when it came to reloading different types of cartridges.
When I first read the part of different types of primers and cases, I did not have a clue what they were talking about.
Don't give up and most importantly, if you have a question, make sure to ask. The majority of the post here are helpful and positive. They answered your question.