I tend to snap back, and then regret when I see that I have hurt the other person.
Recently, I was reprimanded for "little digs" to my ex-bf.
I thought the comment was positive. ("I'm glad Bar has convinced you that birthdays are important to people.") History... in 20 years, I don't think I've gotten a single birthday card/dinner/acknowledgement. (not completely true... I'm sure at some point I announced "today is my birthday." and he said, "Happy Birthday." ) He spent her birthday with her, bought her furniture, dinner and ... well... probably more..
He thought that comment was rather...umm... mean.
Sometimes what we say, even when we've carefully chosen the words... it offends/irks/annoys the listener.
Sorry for the ramble... just starting my second cup of coffee..