What's next? Appearing too cheery in your mug shot?
Personally, I have taken a course on getting arrested. How to behave, what to do, how the system works, the psychology involved, and so on. I've never had to use it, but it's very helpful just to know. I would make the policeman's job as easy as possible. For it is not he who has the power. He only has the authority for a very brief period of time. Let him enjoy it.
Really good advice that could prevent personal injury.