One can both be polite, answer smaller questions, and still protect one's constitutional rights. Its not that hard. Be polite, courteous etc. If it gets more serious, remain polite and courteous, but politely assert your rights. It won't stop an arrest, but it will preserve your rights under a bad search/arrest.
Key words are "be polite, courteous, etc". Totally agree, and that is also the opinion of legal experts, but legal experts do not suggest that you "answer smaller questions, and they will not agree that "It's not that hard". Anything you say can hurt you, nothing you say can actually help you. Watch the video.
Immediately freaking out is not going to be helpful. Pragmatically ticking off the cop is going to make things go bad. legally, dpeending on your behavior it may start the fun chain of reasonable suspicion and again everything can go down hill.
The easiest thing to rember, which will help you from freaking out, is to remain polite, but insist a lawyer or your lawyer be present before you answer any questions. Cops understand that, and if they are questioning you, they are trying to establish a reasonable suspicion (they don't have it yet). Talking to them about circumstances that you are sure can't encriminate you in some way, may incriminate you in some way. Ask any lawyer!!!