I've always been very careful not to (or at least not to intentionally). I'm someone who won't "verbally hit below the belt" because I know words cannot be taken back.
The problem with that "philosophy", however, is that if I'm in a verbal "thing" with someone who DOES say hurtful things I come across as the one who can't keep up my end of the battle because I chose to remain silent or walk away (one or the other). So, I look like "the loser" to the other person; and I feel like "the loser" in the situation.
It's easy to become the "victim" of verbal bullying when you won't say something that's "good and hurtful". Inside, you know you're the better, more reasonable, and stronger person. Outward appearances, however, make you look like someone who can't win the argument, no matter how reasonable you remain. After all, a lot of people don't argue in a civil, reasonable, reasoned, way.
On the whole, though, I don't believe being angry is ever an excuse to say hurtful things. Expressing anger, yelling, whatever - all part of being angry. Going for what we know will hurt someone (or hope will hurt someone) is another thing.