One big difference between the Catholic me and non-Catholic me is
holding myself accountable for my words (the good and the bad!). Although I was never a bad person, when I was loose with my tongue (which is all too easy on the internet), I never really felt bad about it, and I certainly didn't apologize. After all, the person usually deserved it, so why should I? It was certainly much easier than apologizing, too. Apologizing is embarrassing, frankly.
I'm certainly not perfect, but when I find myself in those situations now, I pray, then I swallow my pride and apologize. Sometimes the apology is accepted and sometimes it isn't, but that's really irrelevant. If my words have hurt someone it's not only an offense against them, but against God. We all have inherent worth and dignity because we are created and loved by God, so to strike with cruel and careless remarks is to strike against God.