What I see and hear a lot, is that people get FD'd because: 'Best kill him, or he'll get back at us,' and while I made it a general rule to myself not to FD unless it's a life threatening situation or when the character doesn't bend or shape to your will in any way and doesn't grab the opportunities I give them to get away safely. That's however not what this topic is going to be about, even though it will be brought up as a related issue.
The real problem seems to be when you decide to subdue someone. I think I speak for a lot of people when it's entirely reasonable for you to FD' someone, but do not because the IC reason is somewhat lame OOC. "He has offended my God. My sister. My mother. Called me ugly. A no good. He broke my heart."
It's something I don't FD over until a certain point. Instead, I subdue. I have my ways with them; in my most recent cases, try to have them convert to a God, or at least away from their own if opposing mine. Humiliation, fear, shame. It's these aspects I find to be missing with a lot of my victims. When I subdue someone in a rather short amount of time, I know if I'd be in the person shoes I'd be impressed. Scared. But I'm not.
What bothers me; not a lot, but still enough to open up a topic to draw some attention to the subject, is the following:
You subdue a person. You let him live, don't take any of their possessions; (attempt) to drill some fear into their minds which shouldn't likely be too hard when they are down at the floor, you make them do something. Apologize, convert, acknowledge you as superior. Whatever. Only to find out later that, whaddayaknow, the character has set his mind on killing you.
"You let me live. Now you'll die." It's something which in most cases I find entirely lame. It's showing no courtesy towards your engager; and it happens far too often. It's slowly forcing me to consider the player behind the screen. What kind of a player is he- Someone who's the type of person I suspect to know he will know some fear and back off from his offender, or the type who; after promising to back out of your business IC only gets up to kill you and drive everyone up against you. When someone offers you a way out of death which in 99% of the cases is entirely reasonable, it's only fair to offer him the same. It would lead to a much higher potential of RP and would certainly increase the enjoyment and excitement of PvP you get.
[PS: I'm not dead.]