An insight I had when trying to talk about Sacrifice with a student last week. We were pondering why God who, logic would tell us, couldn't possibly need anything that we have to offer. I mean, I'm pretty sure God doesn't need meat, and if God did, then God has access to some pretty good barbecue, without me throwing my bull on the altar. Right?
I was trying to explain the idea that, just maybe, these rituals were for us, not for God. I've talked about that before. Plenty. But, I then linked it to the Ben Franklin effect. In short, Franklin discovered (or, maybe just relied upon) the fact that the most effective way to get someone to like you is not to be nice to them (which most of us would assume to be the case). Far more effective is to get them to do you a small favor. When they do the favor, they become more likely to have nice feelings for you.
It's almost Pavlovian (I think). Usually, we do nice things for people we like. So, if you do something nice for me, something in your brain makes that association, and starts thinking "Hey! I must like this person."
I'm pretty sure that all of our religious rituals work on exactly this premise.