So I've been reloading 38/357 and 9mm. So far so good at 4k+ rounds. Thinking about reloading 223. I keep hearing about stuck cases, and then seeing the carnage that follows as people try to get the cases out. My questions are.....

What is the most important part to make sure it gets lubed? Is it the neck? The body? The shoulders? Inside the case mouth? All? Never done any bottleneck cartridges and still need to buy dies, lube, case trimmer etc, but I was trying to figure out what probably causes most of the stuck cases. Thanks for any replies.