The cost of "talking out your ass"
The cost of "talking out your ass" is that you will soon find yourself defending the indefensible.
You might have no investment in your stated opinion before you give it voice. Your motive may have been to simply pass time or perhaps to shock the others in the conversation or maybe you are resentful of other's confidence and simply want to "take them down a peg."
The more tenuous the position the more ferociously it must be defended lest you lose face.
The more invested you become, the harder it is to reverse directions.
Ultimately you lose all respect from those whose opinions matter.
Just don't go there.