Having read the posts to date, I'll add:
1. Find a system (faith points) to reward Bob for playing a cleric, or grant abilities only after satisfactory play. Really, I can't figure out why the "Bob sells his celestial lion to a circus" scenario is such a problem. I have had such characters in my campaign, they're called "fallen paladins" and they make great raw material for death knights. Granted, some of the subtleties of really taking an interest in your faith would be hard to police - but alignment issues are pretty easy - all it takes is some will as a DM to enforce the rules.
2. Consider that a "total combat machine" is really a legitimate character type and so Bob is playing his character according to a "total immersion" style if you just would accept what his character really is - a combat machine. Now such a character is somewhat boring, I'll give you, but I would suggest looking to the other players for entertainment. Finally, if you're a DM, consider playing your NPCs - deities included - with the same total immersion style that you expect from your players. Stop fretting about the player acting insane and instead have your NPCs react as if the character were insane.
Bob: "I have rights."
NPC Tyrant: "Really? So then you must be a member of the nobility. Great, then tell me what your lineage is so that I may confiscate your property as you're being executed."
Ie - if the DM stays in character then it doesn't really matter if the player wants to learn the campaign culture or not. Granted - ideally you'd want the player to recognize that the Bill of Rights does not apply to your fantasy world, but even hard-headed players IME will eventually stop bringing it up once they're tired of NPCs laughing at them.
1. Find a system (faith points) to reward Bob for playing a cleric, or grant abilities only after satisfactory play. Really, I can't figure out why the "Bob sells his celestial lion to a circus" scenario is such a problem. I have had such characters in my campaign, they're called "fallen paladins" and they make great raw material for death knights. Granted, some of the subtleties of really taking an interest in your faith would be hard to police - but alignment issues are pretty easy - all it takes is some will as a DM to enforce the rules.
2. Consider that a "total combat machine" is really a legitimate character type and so Bob is playing his character according to a "total immersion" style if you just would accept what his character really is - a combat machine. Now such a character is somewhat boring, I'll give you, but I would suggest looking to the other players for entertainment. Finally, if you're a DM, consider playing your NPCs - deities included - with the same total immersion style that you expect from your players. Stop fretting about the player acting insane and instead have your NPCs react as if the character were insane.
Bob: "I have rights."
NPC Tyrant: "Really? So then you must be a member of the nobility. Great, then tell me what your lineage is so that I may confiscate your property as you're being executed."
Ie - if the DM stays in character then it doesn't really matter if the player wants to learn the campaign culture or not. Granted - ideally you'd want the player to recognize that the Bill of Rights does not apply to your fantasy world, but even hard-headed players IME will eventually stop bringing it up once they're tired of NPCs laughing at them.