just because you have chosen to live a life of "100% honesty" and have chosen to follow every rule out there doesnt mean the rest of us has to whenever we encounter you. You are handicapping yourself for your own personal moral and ethical reasons. Dont be a mormon, just because you have to wear full body underwear and cant watch MTV doesnt mean we have to and cant.
Also, being a douche bag to people on a righteous crusade isnt going to make people change their ways. if anything its going to make them want to blow you off. Tone it down a notch. If you would have handled the sale differently awesome, way to go for you. but you werent selling the bike. You bought it, without a bill of sale. That was YOUR DECISION. its just like the other thread about the 20$.
I am not saying its ok to scam someone out of 20 bucks or not write you a bill of sale. I am saying its your fault for not receiving what you needed at the point of sale.
P.S. Unless you are trying to get brownie points with your god by personally enforcing the american justice system i wouldnt take this guy to court. that is just about the biggest douche bag move on the planet. dont be a baby. maybe if you didnt threaten the guy and tell him he had down syndrome and were a little more patient you wouldnt be in this mess anyway.