I've encountered an interesting phenomenon when playing Halo Reach MP. In many instances, an opposing player will take the time to kneel next to my body and pray after they've killed me. Sometimes they even kneel directly over me. If it's a team game, sometimes another player of the opposing team will also join their teammember in kneeling next to or over me. They'll often stand and kneel several times in a row.
It's just a game! There is no need to do this. You haven't really killed me, just my avatar. Besides, in a few seconds my avatar comes back to life as if nothing happened. Really, I don't mind if you don't kneel when you kill me.
Also, this is dangerous for my opposing team. Often times, members of my own team will not give opposing teammembers the courtesy to let you finish what you are doing. They have no qualms of killing opposing teammembers in a kneeling position, even though the opposition is trying to be polite after a kill.
What puzzles me however is that none of my own teammembers have ever had the courtesy to engage in this polite behavior after they have betrayed me.
Anyway, it's just a game. There is no need to kneel after every kill.