Okay, this is _really_ trivial, but I wanted to ask anyway, because, well, because I am a fool for curiosity I suppose.

While browsing the forums sometimes I see the message "You have liked this post" come up because I happened to click on the link without intending to do so; I am just trying to scroll the page but my pointer accidentally lands on a spot that results in this message.

I have also "liked" a post intentionally, a few times, but that is not relevant to the current question.

If I "like" a post completely by accident, is there any way to "undo" that, or is just fated to remain as such?

No.

Okay, thanks for the info!