Knowing your rights can be the difference between winning and losing a criminal case.  In an attempt to get a conviction police officers will push at least as far as they are legally able to.  By knowing your rights you can limit the amount of evidence that can be used against you in a case and get an attorney at your side as soon as one is needed.  While asserting your rights always be respectful to the police officer(s) and be sure to remember each time you think an officer has exceeded his authority.  The ACLU provides a great outline of what your rights are and how you should handle interactions with the police. 

https://www.aclu.org/know-your-rights/what-do-if-youre-stopped-police-immigration-agents-or-fbi