I always assume that little message is referring to notifications from user groups (get a lot of those), so I tend to be surprised when I see that the Quote section of the inbox is the one with a new message (or multiple new messages). At that point, my usual reaction is "Oh great, now what did I say that someone is responding too?". I don't tend to produce a lot of genuine acrimony though, and I pointedly avoid the various breeding grounds for demagogues and zealots so most of those quotations are positive or at least fairly cordial, but I still sort of dread finding out each time it happens.
And it happens a lot - the inbox has long since started deleting old notifications so I can't really check anymore, but I think it wouldn't be unreasonable to suggest that for every 4 posts I make someone will quote me once. Apparently I say things people feel the need to respond to a lot? But hey, at least I know that somebody was reading those things I said for whatever mad reason inspired me to type them, so that's nice I guess.