That's a good question and you've already answered it with the word "polite". We are all adults and should be aware that a difference in opinion does not require a personal attack. There are always going to be times when people either 1)need to agree to disagree or 2)use the "Ignore" button. Either works for me.

Sidenote: just because a post can be taken the wrong way does not mean it should be taken the wrong way. Give everyone the benefit of doubt in that they really weren't attacking you ("you" used generically). The benefit of this is that if they weren't attacking you you won't look foolish and if they were attacking you it will really irritate them that they weren't successful.

-Blast