Please do not touch any of the Amazon Fulfillment Center Biological Cybernetic Components who are currently in the Behavioural Reprogramming Cells. Their neural pathways are being incentivised for your benefit, to pass savings on to you, the consumer.
Yes, the screaming is perfectly normal. They are screams of delight at their newfound +1.5% picking efficiency.
Of course they feel fulfilled in their work. They feel *extremely* fulfilled. (crackle) Don't you, Unit #417326?