Perhaps most people don't think about it when they curse or use God's name—but that's the problem! God is far too important to treat casually or as if He doesn't matter.
In other words, cursing or using God's name in vain is usually an indication of something much deeper: a person's true attitude toward God. When someone ignores God and decides He isn't important, then they won't see anything wrong with cursing or blasphemy. The psalmist wrote of the ungodly man who "loved to pronounce a curse. ... He wore cursing as his garment; it entered into his body like water" (Psalm 109:17-18). Cursing may also be a sign of anger or hatred, which isn't honoring to God.
But now that you have given your life to Christ and made Him the center of your life, you love God, and you take Him very seriously. And because you do, you dislike it when people treat Him disrespectfully. The Bible is very clear: "You shall not misuse the name of the Lord your God" (Exodus 20:7).
At the same time, pray for your friends when they use language that dishonors God, and ask God to help you show them His love. Remember: You were once like they are, and their greatest need is to turn to Christ and make Him the center of their lives. The Bible says to "bless those who curse you, pray for those who mistreat you" (Luke 6:28).