And I thought I was Immature...

[Oxylepy]

Wow, that must suck. Plus its illegal for the Cops just to stop you for no reason like that you have to be doing something illegal.

Look up the 4th Amendment. If a Cop does that ever again and you did nothing illegal I would ask him why I was being stopped and if he says some thing that is not illegal just walk away.

I get stopped by the cops all the time when wandering around at 3am in the morning. And the Fourth Amendment has nothing to do with them stopping you to talk, it has to do with search and seizure. They are entirely within their rights to stop you to talk to you, especially if they think you're suspicious. Not responding to them could, likely, lead to a lot more trouble than it's worth.

From wikipedia:

Under Terry v. Ohio 392 U.S. 1 (1968), law enforcement officers are permitted to conduct a limited warrantless search on a level of suspicion less than probable cause under certain circumstances. In Terry, the Supreme Court ruled that when a police officer witnesses "unusual conduct" that leads that officer to reasonably believe "that criminal activity may be afoot", that the suspicious person has a weapon and that the person is presently dangerous to the officer or others, the officer may conduct a "pat-down search" (or "frisk") to determine whether the person is carrying a weapon. To conduct a frisk, officers must be able to point to specific and articulatory facts which, taken together with rational inferences from those facts, reasonably warrant their actions. A vague hunch will not do. Such a search must be temporary and questioning must be limited to the purpose of the stop (i.e., officers who stop a person because they have reasonable suspicion to believe that the person was driving a stolen car, cannot, after confirming that it is not stolen, compel the person to answer questions about anything else, such as the possession of contraband)

Also there are laws against vagrancy and as such if a person cannot present information as to where they live/work then the cop could potentially take them into custody.