i have witnessed how both action and inaction can inadvertently cause others to assume all sorts of things. its easy to see that a particular action can cause confusion. actions are easy to spot - someone slapping someone tends to make a pretty strong statement, as does actions that are less direct - like someone making snarky or rude comments to you. its the inactions - the accidental snubs that are the hidden ones. we've all seen them, and we've probably all at some point been guilty of them. what am i talking about? how about a very typical example: someone walks into a bar to meet a group of people. one of those people is so engrossed in a conversation that they end up forgetting to acknowledge the arriving party. or, in a more internet based scenario, someone IMs someone with a query and fails to get a response. or to focus it much more on LJ, someone posts a comment expecting a response, and does not get one.
i think inactions are much more the result of taking friends for granted. the familiarity of friendship can breed this - the oh, they're always around. they'll always be around mentality. i know i do it. i am also a bit more clueless in person at times. you know, spacing out, or being too busy to remember to set an away message or turning on the idle indicator on my IM. But i know it bugs me when it happens to me, so i should try not to do it.
and yes, like all introspective posts, there was a catalyst. actually there were many. within the last few days i've seen examples both with me, my friends, and their friends that have caused me to go Hmm... so i write this in hopes that someone will read it, and in turn be more conscious of their inactions