Papo offered his best rat-smile to the customer. “This Papo has received proper payment in exchange for your purchase, valued customer. This Papo hopes that you found its service satisfactory, and wishes you a productive and enjoyable day.”

  The adventurer pocketed his change and the potion he'd just purchased. “You know it, Paps. Your endurance potions are the best; all the energy, all day long.” He grinned. “Or, in this case, all night long.” He gave the rat-controlled golem a two-finger salute and stepped out the shop's door.

  Papo filed away the purchase on the ledger, even though it had been securely recorded in his expansive mind; one could never have enough copies of transactions, after all! He put the money away into the register and wiped the counter clean with a light disinfectant, lilac-scented.

  Customers were 11% more likely to purchase complementary potions in the afternoon when he used the lilac disinfectant. Citrus was best for the morning and the weekend.

  His internal bell-clock said it was half past the thirteenth bell. Another half bell before mistress Linzy returned from her midday break. He looked at the wall clock to confirm his internal time was accurate, and found that it was. Good.

  Gerat's voice piped up inside his head. “Oppressing machine mind! Have you given thought to my proposition?! The brute and the anomaly are gone, along with their metal pet! No one can stop us from taking over this settlement!”

  Papo gently shook his rat head. “No, friend Gerat. I already mathematically demonstrated that this was the wrong course of action. Also, it would make Mistress Linzy and Niala sad. I am sorry. Maybe we can devise a plan that would benefit everyone?” The consciousness offered.

  “I AM NOT YOUR FRIEND! I am your unwilling prisoner! Within my own head! Forced to listen to your rambling respect! It is straining my ego to rupture!”

  Papo waited for the second part to come. It always did.

  Gerat's voice was pleading when he spoke again. “Please, machine! Just a minuscule conquest! A single cellar! With three minions, at most! Just enough to seed a new under-hall of the arts! I beguile you!”

  The little rat smiled. “No, friend Gerat. Conquest is not equivalent exchange. We cannot do this. Do you require my assistance in finding a new plan?”

  Gerat devolved into a half-mad rant about the rat-golem's inability to grasp the greater certitude.

  In truth, Papo didn't really understand a good portion of what friend Gerat said, but the near-constant presence in his head was... desirable.

  He had even learned a new word lately, which better described his... feeling, about this situation: soothing.

  Gerat's constant presence and raving lunacy were soothing.

  Before coming here, to Mistress Niala's residence, before Gerat had found his repository and somehow merged his mind with him, he had been alone for a long time.

  After the last of the facility's staff had left and sealed the repository, everything had gone into standby mode. All the sounds and movements that had characterized his tenure had ceased. He had been left with stillness, with only the passage of time to occupy him.

  He had busied himself with counting the seconds, his mind desperate for something to do. After a while, once he had reached ten billion seconds, he began speeding up or slowing down his counting, and then comparing his active count to his internal clock, acting surprised when it didn't match, and starting over again. He would then count up to a number of seconds he had decided in advance, a small number, like two or three million, and start a parallel process, in which he counted more.

  The author's tale has been misappropriated; report any instances of this story on Amazon.

  He made it a game to see how many parallel processes with an accurate second count he could hold before encountering errors.

  And then, he would set up convoluted rules, making the second-counting more challenging.

  At the time, he didn't know, but he now knew he had been terminally bored. Mentor Jordo had explained to him that it was to be expected; a central consciousness such as Papo was made to manage an installation's daily operations with an almost manic dedication.

  To be suddenly left with absolutely nothing to do... Jordo had been surprised at how stable Papo's core had been, after they'd run the self-diagnostic; 93%. Given his experience, Jordo claimed this was the mark of a top-rated consciousness.

  Papo had found the concept validating.

  However, something strange had happened since coming to rest in this biological body. His core stability had rapidly degraded, now hovering just above 70%. Perhaps he should have been concerned at the accelerated drop, but somehow, Papo felt that it was fine. A living thing was not meant to have a core stability in the nineties.

  He would know; there had been a complete archival section dedicated to experiments on calculating and adjusting a humanoid's simulated core stability. Anything above 75% would end up creating sociopaths.

  He didn't want to be a rat sociopath. He liked his new friends too much.

  Sure, they didn't always follow the rule of equivalent exchange, but Mistress Linzy had taught him a new concept, which he found increasingly useful and appropriate when dealing with organic beings. The rule of equivalent non-measurable exchanges.

  She had explained the rule to him once, when he had asked why she kept smiling at customers who had purchased something and were leaving. He understood that smiling before the transaction was a way to improve the odds of a purchase, but once it was complete, why expend more energy?

  She had said: “Salesrat Papo, some things can't be measured. A smile cost me nuthin', but if that's tha last thing tha customer sees when leavin', that's wha' he'll remember about this place, and who doesn't like a good smile?”

  He had still been unconvinced; after all, how could you prove something that cannot be measured? Mistress Linzy had taken this as a challenge and had run a little experiment with him. Over the next few weeks, she gave a parting smile to half of the new customers, and not to the other half. She told him to keep track of those customers and to compile their data.

  And the data hadn't lied; the ones who had been wished well with a smile had been 15% more likely to return, and spent 21% more than the ones who hadn't been smiled at.

  He had then countered that those were numbers, and thus a parting smile could be measured. She had replied that if you went to a different store and did the same experiment, you'd get similar, but different results.

  And he had understood then; if an experiment was run with the same parameters but had different results each time, then there were unknown parameters, and unknown parameters could not be measured.

  Thus, a smile's value could not be measured, but it could be assigned an arbitrary value. Only, the value depended on the one who received it.

  And so, Papo had begun offering smiles, after learning how to smile as a rat, to everyone he could. The results had been staggering; customers had begun treating him like a humanoid, confiding in him some of their daily lives, and even a few secrets. It had been apparent that organics greatly valued smiles.

  The most perplexing thing, however, was that, as he offered smiles and received them in turn, he found them increasing in value. To him.

  To the point that optimizing how to increase return smiles had become his primary directive, without even assigning it to his primary process. A sure sign that his core stability was degraded. And he found himself lacking any motivation to address the situation. In Mistress Linzy's words, he didn't give a rat's ass.

  He just wanted to smile, and get a smile in return.

  If he could have that, if he could make everyone return a smile at him, his core stability could drop to zero, and he would be fine with it.

  The door opened on one of his regulars, Aldan, a gruff adventurer who pretended to dislike everyone, but who, Papo knew, always made certain to show up when he was at the counter.

  Papo smiled at Aldan.

  “Greetings, valued customer. What can this Papo do for you on this day?”

  The gruff adventurer's frowning lips ticked upward. Still a frown, but a bit more of a smile, as well. A little win in the battle to get a smile out of the man.

  Yes, smiles really were the best.