Getting case lube inside the case can cause the powder to fail to ignite properly, even though the primer goes bang.
Bullet may stay in the barrel, get stuck between cylinder/chamber or you get a Swoosh.
A Swoosh is when some of the powder ignites just enough for the bullet to go downrange and hit the target, but it's a quieter bang and softer recoil.
I named that a PMS load.
Poor Man's Silencer.
Getting too much lube in a Casing, will ruin the taste of the sausage.
I often have people walk up behind me,
while shooting the 460, and they scream,
"IS THAT A 500?"
Shooters close by stopped shooting as well.
The Mrs solved that problem with this on my the back of my shirt.
pic is of an early one before we bought a GEO KNIGHT heat press.