[chrisseaton]

> That's a funny example, as it can be read both literally ("I like it."), and passive-aggressively ("I don't dislike it.").

You seem to have those backward.

"I don't dislike it" is what it literally means. That's the opposite of being passive! "I like it" is reading an implication which isn't literally there and is more passive.

There'a a really important difference here. Someone can not think that something is not unwise, but that does not mean they think it's wise. A double negative does not cancel out - you loose important literal meaning when you do that - not even just an implicit idiomatic meaning.