Actually, one of the things that counselors advise is to phrase things in terms of "I feel" statements -- this is supposed to be seen as non-aggressive and non-accusatory.
"I'm a little surprised you'd think that I'd be okay with baseball-game tickets on our anniversary," is a very, very mild thing to say, for example.
I know I'm disagreeing with the majority here, but I think that "I'm rather amazed by the strong reactions I'm getting to X post" is a very appropriate thing to say on an etiquette board, especially when you are genuinely feeling surprised.
I'd love to hear suggestions of a better way to phrase this statement. Genuinely asking, not being snarky, honest.