Parents do their best to raise their teens with morals, values, and ethics.  What happens when you don't practice what you preach?  For example, if you abhor name calling, but you call someone a name, how is this practicing what you preach?  It's not -- you're being a hypocritic.

Teens are smart enough to recognize that parents may say one thing but mean something else.  You tell your teens to be polite and treat people with respect, but you bad mouth people at the office or online, your spouse, your sibling, or friend.  It doesn't make sense to teens.

Practicing what you preach will show your teens that you "walk your talk."  How will teens respect you if you tell them not to do something but you go ahead and do what you told them not to do?  Teens will lose respect for you because you did the opposite of what you expect them to do.

Like it or not, your teens obseve your actions.  This is how they learn.  If you're not kind to someone, they'll pick up on that and believe they can treat people without respect.  If you're negative all of the time, the negativity will rub off onto them.  Before you know it, you're living in a toxic environment that's not safe for anyone.

Teens need good role models in their life so they'll become upstanding and productive citizens.  Moms and dads, you're responsible for guiding their teens through life and shaping their values system.  Do the best you can -- start by practicing what you preach!