"So... you are in a relationship with a human?" Cas said.
"I am as well."
A pause. Then Spock admitted, "It does have its challenges."
"I have noticed," Cas said.
"Humans are ... very emotional," Spock observed, "They are not always ruled by reason."
Cas nodded. "Some of them don't seem to be ruled by very much at all."
Spock let just the corners of his mouth turn up slightly as they stood in silence again, watching Dean and Jim.
Cas eventually said, "Humans like to be lied to sometimes. They say it makes them feel better."
"Unadvisable," Spock declared evenly, "Lying to others - or to oneself- is an irrational way of dealing with problems."
"So you think it's best not to indulge them when they're being exceptionally ..."
"Human? No. If you let them have their way too often, soon all you'll be doing is talking about your feelings, and submitting to to their unscientific experiments to see how you behave in altered states."
"So you would tell your human if you felt he were being, as the humans say, a 'dumbass'?" Cas said.
Spock paused. "Only if saying so held a likelihood of altering a course of action."
Cas nodded as they continued to watch Dean and Kirk pummel each other, breaking most of the low-quality furniture in the bar in their dispute over which musical group was superior.
"Shall we discourage this behavior then?" Cas asked.
Spock shrugged. "Might as well let them get it out of their system."
Cas paused, then nodded. "Sounds logical."