What's the big deal about profanity?

Three letter posts, texts, spoken "words" come at us constantly and have become so ingrained in our daily lives most of us do not even think about them.  I refuse to even put their letters here because they make me think the words that go with them.  They are not just innocent letters. Even now, I apologize if the thought of them makes you think those words.  Words matter.  

"Do you not understand that everything that goes into the mouth passes into the stomach, and is eliminated? "But the things that proceed out of the mouth come from the heart, and those defile the man. "For out of the heart come evil thoughts, murders, adulteries, fornications, thefts, false witness, slanders."  Matt. 17:17-19

Ouch.  I have used, abused, and spewed out words.  As I get older, I realize the intense power of those words.  And I ponder profanity.  My parents had "rules" - don't say this, always say that, etc.  Unfortunately I learned to obey the rules only, and didn't really understand the reason behind the rules.  It is the kind of thinking when I thought that the Ten Commandments were "don't"s and not understanding that they are all about the difference between our sinful nature and God's Holy One, and that only a loving God would give us rules so that we could find truth. 
and love. 
and joy. 
and eternal life.

Profanity - the opposite of sacred.  I don't want to be profane.  Actually, I desire holiness, sacredness, righteousness, Godliness.  That is the sad part about being surrounded by profanity, the sad part that we are not taught the difference between sacred and profane, respect and selfishness, courtesy and rudeness.  Our culture has trampled on the sacred under the banner of "rights" and "freedoms".  I am thankful for the rules my parents set - we were not allowed to say "dang it" or "darn" because they explained it was simply a more "acceptable" way of using a swear word.  They explained less (if at all) about why using the curse words was profane.  It has been only recently that this hard heart of mine has absorbed the full reality that profanity in any sense is the total epitomy of selfishness.  It does not consider the sacred nature of our own minds or hearts, the sacred in others, the sacredness of what our society could be if it was redeemed by the Redeemer of all.  The profanity of others dirties my mind and heart, but also makes me wonder at why I am not more careful with my words, too.  It reminds me that we are all in need of mercy.  
and grace.  
and redemption. 

"Set a guard, O Lord, over my mouth;
    keep watch over the door of my lips!"  Psalm 141:3