We operate a pool. We don't charge for it, and we're providing a service to users... So yes, it' about "irrational emotions".

The theory behind a score based system assumes that you're continuously mining, and continuously submitting shares at roughly the same average speed (give or take some variance) in order for it to be fair, after an extended period of time... and it is. I'm not questioning that.

However, in order for it to be fair for all miners, casual or hardcore, continuous or sporadic, you have to make each share retain it's value for the full duration of the round.

Pay-per-share is also an entirely valid method, but it's a gamble on the part of the server administrator.

So, to break it down:

1) Score based - Fair over time for continuous users, more beneficial immediately for faster GPUs vs slower CPUs, less risk of exploitation
2) Share based - Fair for all users immediately, CPU or GPU. Possible risk of exploitation if not protected against.
3) Pay-per-share - Fair for all users, but poses a potential risk to the pool operator in regard to loss.

Each is fair, with it's own benefits and concerns. We chose #2 in this case. If you don't like it, go somewhere else that suits your needs/wants/desires more.